quality Fire Refractory Bricks & High Alumina Refractory Cement factory

It’s well known that mullite lightweight bricks are used in insulation layers to play a role in heat preservation and energy conservation. However, in furnace linings with low corrosiveness, they can be used in the working layer (the area directly in contact with the flame).   For neutral furnace linings, JM23, JM26, JM28, JM30, JM32 can all be used directly in contact with flames. Especially the bricks of JM30 and JM32, like alumina hollow sphere bricks, can be used in high temperatures. Currently, the bricks which used in the insulation layer on the market also have clay lightweight bricks and high alumina lightweight bricks. The mostly used insulation layer brick is clay lightweight brick. Since the thermal conductivity of clay lightweight bricks and polymeric lightweight mullite bricks is not significantly different, it is only necessary to select lightweight bricks of the appropriate material density at the right temperature.     Polymeric lightweight mullite bricks are high-end insulation materials. Moreover, when the furnace temperature is high, choosing polymeric lightweight mullite bricks with different bulk densities and different service temperatures can all play a role in insulation and energy conservation. In some special furnace linings, especially the outside temperature of the furnace is low, mullite lightweight bricks can be selected for both the insulation layer and the working layer.   However, for some strong acid and strong alkali furnace linings, the working layer is not suitable for using lightweight bricks. That’s because when the corrosiveness is high, the strength of lightweight bricks is not strong, and the corrosive slag will erode through the lightweight bricks. But if alumina hollow sphere bricks are used, they can also be used.   Based on the current market usage, mullite lightweight bricks are mostly used in insulation layers. Under conditions where the temperature outside the furnace shell is required to be low and the temperature and environment are suitable, mullite lightweight bricks can be selected. They can also be built in multiple layers. JM23 can be used for areas close to the furnace shell, and JM28, JM30, and JM32 can all be chosen for flame usage. It is segmented and itself serves as an insulator. It’s lightweight type and the performs even better when used in light-duty kilns.

Clay brick is made by clay clinker and soft clay as a bond aluminum content of 30-48% stereotyped refractory. The particle composition of clay brick is generally more coarse and fine particles, and less medium particles, which ensures the strength of the brick and improves the thermal shock stability.     The low porosity clay brick is based on the clay brick raw materials, and adding a certain proportion of coke gems to adjust the porosity to ensure the density and corrosion resistance. Low porosity clay brick has lower porosity and higher density, and has significantly improved the compressive strength, durability and thermal insulation performance than clay brick. Low porosity brick has higher compressive strength and can withstand external pressure better. Because of its low porosity structure has higher density, it is better in durability and fatigue resistance.   In the production process, low-porosity bricks and clay bricks are basically the same, but in the process ratio of more coke gem components, in the forming process is the same, but raw material selection and firing molding, raw material selection is more strict, after adding coke gem raw materials, the sintering temperature is slightly increased.   Low porosity clay bricks are mainly used in erosive environments, such as glass kiln heat storage chamber with large usage and obvious use effect; Clay bricks are widely used in the permanent layer of all furnace linings, and can also be used in flue and weakly acidic environments. If the two kinds of refractory bricks are to be compared from the use of low-porosity clay bricks can be used in higher requirements of the furnace lining, clay bricks can be used in ordinary parts. If only from the quality point of view, low porosity bricks than ordinary clay bricks durable, better quality.

Under normal circumstances, the calcination belt uses bricks with a body density of more than 2.9, the transition belt uses 2.6 body density of ordinary phosphate bricks or high aluminum bricks, there are also the use of magnesia-aluminum-chromium bricks, but because magnesia-aluminum-chromium bricks are expensive, the selection of manufacturers are not many, more than 95% of the use of special phosphate bricks. However, if from the use cycle, it has been a question that can not be answered precisely, because the raw materials used in zinc smelting are different, resulting in the use cycle of the lining material can not be determined.   The raw materials used in zinc smelting rotary kiln can be basically determined by region, under normal circumstances, Jiangxi, Hunan, Hubei zinc smelting raw materials are zinc ingot, zinc slag, coke powder, or blast furnace gas dust, zinc oxide ore, coke powder, the two raw materials used in rotary kiln, after 1000-1300℃ high temperature reduction gasification, and then condensation treatment to zinc oxide. The service cycle of the rotary kiln produced by these two raw materials is relatively long, generally more than 10 months. However, if the raw material is changed halfway, it is not possible to determine the use cycle, or the raw material measurement is not accurate, and the forklift does not measure the mixture in production, it will also increase due to the degree of erosion, so that the service cycle of the rotary kiln lining is shortened.   The other is the use of boiling furnace acid leaching waste zinc slag, but this raw material is generally in Anyang, Xingtai, Handan area, especially Anyang area, because this raw material in the rotary kiln calcination, impurities and reduction of metal corrosion is too large, and will be in the rotary kiln lump or sheet slag, hanging on the kiln lined phosphate brick, the thickness of the knot makes the kiln diameter smaller, affecting the output. In this case, the manufacturer will wash the kiln, and the washing kiln is a high-temperature slag melting discharge, each washing kiln causes the phosphate brick to erode 6-7 cm, so that the service life of the lining resistant material is shortened. If the kiln is washed half a month, the phosphate brick lining of the rotary kiln will be changed for more than 2 months. If the kiln is washed once a month, it can be used for 4 months.   Therefore, the cycle of special phosphate brick with zinc rotary kiln lining cannot be determined, because the kiln is in a state of high temperature and continuous rolling, the physical and chemical reaction in the kiln is intense and complex, and the kiln lining is seriously worn, but also depends on the raw materials used, the number of kiln washing, and whether to continue to operate.

When the steel brick passes through the molten steel, it must withstand high temperature erosion, and the inner wall will have residues hanging on the inner wall of the brick, and some manufacturers will require the use of two or more times.     However, if the production of poured steel bricks is improved, the flat bottom is changed to the bottom of the pot, so that the circulation is fast, the inner wall will not hang slag, even if the use of the inner wall hang slag, slight knock off the slag, can be reused. However, in the production process, the level of production personnel is a big technical test.   First of all, start from the mold, if the bottom is made live, the casting steel brick is easy to handle, but it is easy to cause the lower part of the brick is not dense, if the bottom of the pot is made dead, so that you can press the bottom porcelain in the process of pressing the brick, but the semi-finished product is not convenient, but in order to be more convenient to use, then use the solid bottom to press the brick, the technical requirements of the brick skilled workers, The brick produced in this way is easy to knock off the inner wall slag when in use and make repeated use.     After the casting steel brick is solved from the forming part, it is the sintering problem, because the casting steel brick has a special shape, it can only be installed in the upper part of the kiln car, so as to ensure that the burned brick does not deform, but this is bound to cause a long burning cycle problem, and only when the upper part also has the appropriate temperature of the underlying brick, it is burned together with the lower brick, so the cost will increase.   Pressed brick, fired brick these two big decisions can be fired out of the appropriate cast steel brick, but one of them is to use two fillers when pressing the brick, if the powder of a filler aggregate is formed at one time, it is bound to cause the brick surface rough, if the first mix a certain proportion of the material pressed into, and then the powder scattered on the pressed surface, In this way, the appearance and inner wall of the cast steel brick are smooth, which helps the flow more smoothly.   In short, the production process of casting steel bricks is more complex than that of ordinary bricks, and the process of pressing bricks is not the same, and then the master of sintering temperature during the firing process can ensure that the product can be used well.  

Casting powder also called mould powder is an important raw and auxiliary material in the continuous casting process, which is called the "industrial MSG" in the continuous casting process by some metallurgical experts. It is one of the three key technologies in continuous casting process. The three key technologies of continuous casting are crystallizer, casting powder and submerged nozzle. After the application of self-casting powder in the continuous casting process, the process of continuous casting has been greatly improved, and the surface quality of continuous casting billet has been qualitatively improved.   The casting powder plays two main roles in the continuous casting process: ensuring the continuous casting process and improving the surface quality of the billet;   The two major functions of the casting powder in the continuous casting process are realized by the five functions of the casting powder.   1. Heat insulation and insulation Adding casting powder to the surface of high temperature steel can effectively prevent the radiation temperature drop of molten steel, effectively increase the temperature of mold meniscus, and obviously reduce the formation or excessive growth of slag ring. Especially in the casting of high carbon steel, it is beneficial to improve the lubrication of the casting billet by improving the thermal insulation performance of the casting powder. The insulation property of the casting powder is mainly achieved by the specific gravity control of the casting powder and the matching of carbon. Generally, the insulation property of the casting powder with small specific gravity and high carbon content is better. 2. Prevent secondary oxidation of molten steel; After the casting powder is added to the mold and melted, the molten steel is isolated from the outside world, thus avoiding the direct contact between the high-temperature molten steel and the air, and effectively preventing the secondary oxidation of the molten steel, which has great benefits for improving the quality of the molten steel and preventing the oxidation of trace alloying elements in the molten steel. 3. Lubricate the billet to ensure the continuous casting process; After melting and being consumed, the casting powder enters the gap between the solidified billet shells and is liquid on the contact side of the casting billet. It plays a lubricating role in the process of casting billet pulling down, effectively reduces the pulling resistance of billet and prevents the occurrence of bonding accidents. 4. Adsorption of inclusions floating in molten steel to purify the quality of molten steel; In order to prevent the inclusions floating in the liquid steel from being sucked into the initial solidified billet shell, resulting in surface or subskin defects of the billet, the liquid slag layer formed by melting of the casting powder should have the ability to absorb and assimilate the non-metallic inclusions floating in the liquid steel, and at the same time make the physical properties of the casting powder change little. 5. Improve the heat transfer structure When using rapeseed oil as lubricant, in the lower part of the crystallizer, due to the shrinkage of the billet shell, the air gap is generated, resulting in increased thermal resistance, reduced heat transfer is very uneven. The liquid slag formed by melting of the casting powder can improve the uniformity of heat transfer and improve the quality of the casting billet. The main technology used to control the heat transfer of the slag film is to improve the basicity of the casting powder, increase the solidification temperature, crystallization temperature and crystallization rate of the casting powder, and reduce the effective thermal conductivity of the slag film. This is also one of the reasons why medium carbon steel basically uses high alkalinity casting powder. The five basic functions of the casting powder are closely related to the quality of the billet and the forward casting process. Due to the improvement of the casting speed and the expansion of the casting steel, these five basic functions have been given a new connotation, so that these five basic functions are closely linked together, and the change of each function will cause the change of other functions.

Bauxite is playing a crucial role as an important raw material in the refractory materials industry, especially in silicon-aluminum refractory materials. In China, bauxite is mainly distributed in Shanxi, Henan, Guizhou and other places. Shanxi and Henan together account for the majority of bauxite reserves.   Shanxi bauxite reserves account for about 43% of the country's total. It is characterized by high silicon and aluminum content, low iron, potassium and sodium content, uniform mineral phase, and after calcination, the content of AL2O3 can reach over 90%, with low impurity content such as Fe2O3 and TiO2. Its refractoriness is up to 1780℃, strong chemical stability, high bulk density and low water absorption rate, as well as high high-temperature strength and good creep resistance. It is more suitable for the production of medium and high-end refractory materials, especially castables.   Henan bauxite reserves are second only to Shanxi, with the AL2O3 content of 60-70%. The silicon content is generally high, and the aluminum-silicon ratio is relatively low, which has some impact on high-temperature performance. The refractoriness is also good, but the volume stability after calcination is slightly inferior. The Fe2O3 content is relatively high, generally maintained at around 2%. In the application of refractory materials, the slag resistance is slightly worse. The quantity of high-quality bauxite with better aluminum content is relatively small. It is more suitable for the production of medium and low-end refractory materials, such as grade two high alumina bricks, grade three high alumina bricks, etc. Some enterprises mix Shanxi and Henan bauxite to reduce production costs, but the specific proportion must be well controlled; otherwise, it will be counterproductive.   When choosing bauxite, we should not blindly pursue price, another important thing is that the product suitable for the working conditions should be selected based on the usage scenario.

Mullite insulation bricks are generally marked with JM, where J is the pinyin “Juqing” for lightweight and M is the pinyin “Molaishi” for mullite. They are mainly used for insulation in the lining of various high-temperature furnaces to improve the insulation effect and reduce energy consumption; Mullite insulation bricks are also used for insulation in equipment such as thermal power plants and nuclear power plants.   But different grades of mullite insulation bricks are used at different temperatures area. According to national standards, JM-23, JM-26, JM-28, JM-30, and JM-32 are generally classified into different levels, and JM-32 is not widely used. The usage ratio of 26 and 28 is relatively high. JM-23 mullite insulation brick with Al2O3 content of 48%, operating temperature of 1300 ℃, and bulk density ranging from 0.55-1.5, with the most commonly used being 0.8 and 1.0 and bulk density. The variation of the linear change on reheating is within ± 1 at 1300 ℃ × 24h.   JM26 mullite lightweight brick, Al2O3≥55%, The operating temperature is 1400 ℃, and the bulk density ranges from 0.55-1.5g/cm3. The most commonly used ones are 0.8 and 1.0g/cm3. The linear change on reheating between 0.7-0.8 at 1400 ℃ for 24 hours.   JM28 mullite insulation brick, Al2O3≥65%, The usage temperature is 1500 ℃, and the bulk density ranges from 0.55-1.5. The most commonly used ones are 0.8 and 1.0 and bulk density. The linear change on reheating at 1500 ℃ for 24 hours at 0.7.   The Al2O3 content of JM30 is ≥72%, with a usage temperature of 1600 ℃ and a bulk density ranging from 0.55-1.5. The most commonly used densities are 0.8 and 1.0. The variation of linear change on reheating is 0.6 at 1600 ℃ for 24 hours.   JM32 is not frequently used and is usually customized for production according to the user's special requirements.   Different grades of mullite insulation bricks are used at different operating temperatures, and different furnace types are selected according to the temperature and operating conditions of the user's kiln. But there are also other indicator requirements, which are produced and formulated according to different requirements of the manufacturer.

The appearance color of fire clay brick just means that the appearance of the surface of the brick is beautiful, and the aluminum content has a certain relationship. But the relationship with physical indicators is not large.   At present, there is a wrong vision in the market, if the appearance of fire clay brick is light yellow color then it’s a good brick, if it’s dark red, the quality is not good. What color does the appearance of fire clay brick show, is related to the process ratio, if you add a high amount of aluminum flour, the appearance of the color will look good, light yellow, giving a person a comfortable feeling, from the point of view of chemical indicators, the aluminum content is indeed slightly higher.   But if the color of the brick is dark red, the appearance size can be, and the weight can also meet the standard, indicating that the internal quality of the clay brick is good. The internal quality of clay brick has a certain relationship with aluminum content and volume density.   At present, the color of fire clay brick in Henan is basically light yellow, the appearance is suitable, and the weight of bricks can also be. The color of the three high aluminum bricks in Shandong and Hebei are similar, but the load softening temperature is slightly different. In fact, if analyzed from the expert point of view, the load softening temperature can best reflect the difference in the quality of fire clay brick. But the load can only be tested to know, unlike the color and weight from the naked eye and pick up with the hand, it is very intuitive to know.   And another indicator, that is, the stomata, can not be intuitively seen, can only be learned by means of inspection, and can not be seen by looking alone. In addition, strength, compressive strength is also tested to know.   That is to say, the surface color of the clay brick is only related to the aluminum content, and has nothing to do with the physical indicators, so only looking at the color is not able to see the internal physical indicators of a clay brick.  

The amount of water adding should be strictly controlled during construction of ultra-low cement castable   Ultra-low cement castable is a kind of high-grade refractory castable, the quality of raw materials is higher than other ordinary castable, mainly reflected in the low calcium content, and the using performance is much better. Moreover, the process ratio is more fine and diversified than ordinary castable. However, no matter what kind of raw materials and ratios, controlling the amount of water added during construction is the most important thing, because the amount of water added is too large, which directly affects the use cycle and performance.   The cement proportion of ultra-low cement castable, as well as other binders and low cement castable are different, there must be SiO2 ultrafine powder and a variety of compounds added, whether it is formulated and strength, will be higher than the indicators of low cement castable. If the ultra-low cement material on site does not set, it’s proved that the amount of water is too large, if the temperature is too low, the temperature can be adjusted appropriately, if the temperature is too high, the amount of water can not be added too much, and the process ratio can only be adjusted according to the temperature in the production process, if the amount of water is too large, there will be delayed condensation.   For example, if the amount of water added is too large, there is no initial setting in 12 hours, the ultra-low cement castable is better than the low cement castable, the cement dosage is only 2.5-3%, the calcium content is between 0.2-1%, the water added in the laboratory is 2-3%, the initial setting time is about 10h; The amount of drinking water added to the site is about 4%, if the amount of water added is too large, there will be no condensation, even in 24 hours can not condense, will seriously affect the construction progress.   Therefore, during the construction process of ultra-low cement castable, the amount of water added must be strictly controlled, and the natural maintenance after forming can not be sprayed. If condensation is a normal phenomenon within 10 hours, the compressive strength after natural curing is generally 6-15Mpa, if the condensation is not or the condensation time is too long, the temperature can only be adjusted in the construction phenomenon, and the water can not be increased.

Intermediate frequency furnace is a kind of equipment widely used in metal melting, the high temperature resistance of its lining material is directly related to the melting efficiency and the service life of the lining. So how to improve the high temperature resistance of intermediate frequency furnace lining? Improving the high temperature resistance of intermediate frequency furnace lining can extend the service life of the lining, reduce the maintenance cost and improve the production efficiency. How to improve the high temperature resistance of intermediate frequency furnace lining 1, choose the appropriate lining material ① Refractory material Selecting refractories with high temperature resistance is the basis of improving the high temperature resistance of lining. Materials such as high aluminum brick and magnesium brick are widely used because of their high temperature resistance, corrosion resistance and chemical erosion resistance. ② Refractory fiber material Refractory fiber material is used as the heat insulation layer of furnace lining because of its light weight and good heat insulation performance. This material can reduce heat loss and improve the thermal efficiency of the furnace. ③ Composite refractories Composite refractories combine the advantages of different materials, such as high refractoriness, good heat insulation performance, chemical erosion resistance, etc., can improve the comprehensive high temperature resistance of the lining. 2, optimize the lining structure design ① Multi-layer structure design By using multi-layer structural design, materials with different properties can be used at different levels to adapt to different working conditions. For example, high-temperature resistant materials can be used for the inner layer, while insulating materials can be used for the outer layer. ② Setting of heat insulation layer Adding insulation to the furnace lining can reduce heat transfer to the outside, keep the temperature in the furnace stable, and reduce energy consumption. ③ Reasonable determination of furnace lining thickness The thickness of the furnace lining needs to be determined according to the working conditions of the furnace and the expected service life. Too thin can lead to premature lining damage, while too thick can increase costs and heat loss 3. Strictly control the construction process ① Construction environment control The temperature, humidity and other conditions of the construction environment will affect the performance and construction quality of the furnace lining. For example, too much humidity can lead to a reduction in the strength of the material. ② The material is mixed evenly In the mixing process of the lining material, it is necessary to ensure that all components are evenly mixed to avoid performance differences caused by uneven local components. ③ Standardization of construction technology Following standardized construction processes, such as the correct pouring, compaction and curing methods, can ensure the compactness and uniformity of the furnace lining, thereby improving its high temperature resistance. 4. Maintenance and maintenance of furnace lining ① Temperature control for initial use When the lining is used for the first time, it should be gradually heated up to avoid thermal stress and lining rupture caused by rapid heating.   ② Check the lining condition regularly Check the lining regularly, check whether the lining has cracks, falls off or other damage, and repair it in time to extend the service life of the lining. ③ Avoid overload use Avoid leaving an intermediate frequency furnace in operation beyond its designed capacity for long periods of time, which reduces liner wear and extends its service life. In summary, how to improve the high temperature resistance of intermediate frequency furnace lining material, through selecting suitable lining material, optimizing lining structure design, strictly controlling construction process and carrying out lining maintenance and maintenance, can improve the high temperature resistance of intermediate frequency furnace lining material. These measures help to extend the service life of the furnace lining, improve production efficiency, reduce maintenance costs, and thus bring better economic benefits.

High aluminum bricks belong to the neutral series of firebricks, because of different aluminum content, there are different levels, but at present, the severe situation of the market, such as third level high aluminum bricks, for different bulk density, the application and price have big difference.   Third level high aluminum bricks aluminum content in 55%, it will not compared to the internal quality of the bricks if only focus on the price when purchasing, because if the bulk density is different, the raw materials and processes are not same, the higher the bulk density, the internal quality of the brick will be better, also lower porosity and higher strength. Different bulk density of third level high aluminum bricks prices are also different, each increase of 0.01 bulk density, the price will increase by more than a few hundred yuan, if the soft load is increased, the price will increase by several hundred yuan, or even thousands of yuan, because what heavy softening temperature and raw materials, sintering temperature, process ratio has a great relationship, the more demanding, the higher the cost of raw materials, the price will also increase.   At present, due to the price war, the three-level brick is only said to compare the aluminum content is more, other indicators are based on different lining and temperature and then volume density, load softening temperature, and then according to different requirements, calculate different prices. If only the aluminum content, the lowest price, and even the aluminum content of clay bricks can meet the requirements of third level high aluminum bricks, but if the demand for physical indicators is high, the price alone will lose the meaning of the quality requirements.   From the actual words of the three-level high aluminum brick manufacturers and market demand, only the use of aluminum content is still a relatively large proportion, and the quality requirements for the full index are rare. In any case, quality and price complement each other, low price is sure to have low intrinsic quality, and the volume density will be reduced.   Therefore, the three-level high aluminum brick can not only compare the price, we must look at the actual use requirements, at the same time, we must notice the main indicators of bulk density, porosity, load softening temperature, and then the comparing will be reasonable.

Welcome Thailand customer visit our factory to check the rotary kiln bauxite cargo and production process, CH Refractories bauxite output every month over 20000tons, can ensure the large quantity delivery time and quality.     The spot stock reserves are large and can be delivered at any time. Different range Al2O3 content can demand different customer's need.       Raw material bauxite ore: select by hand; Grain size：customize new sieve mesh for every customers to guaranteed accuracy. Technical data: Test by spectrograph machine.

The price of high aluminum bricks is determined by the quantity, shape and technical data.   The price of high aluminum brick is determined by different aluminum content, different bulk density, different strength, different load softening temperature and different apparent porosity. Even if it is the same aluminum content, but the bulk density is different, the load is different, the porosity is different,so the price will be different.   During the purchase of high aluminum bricks, it can not only be determined by price, should also considering about the different indicators, especially the bulk density, for example, the value of 0.1, the price will rise by 300-500 RMB, if the difference is 0.2, the price will increase by nearly 1,000 RMB. If the load softening temperature is different, the price will be different from 500-700 RMB. Therefore, the quality of high aluminum bricks can’t be determined only by the price ratio.   When the density of high aluminum brick increases, the raw materials with high density must be added to the production process, and the increase in the load softening temperature is determined by the sintering temperature and raw materials, and in the case of high load softening temperature, another composite raw material process is added to improve the load softness. Adding high-grade raw materials and composite raw materials will increase the price of high aluminum bricks.   In addition, high aluminum bricks also need to consider the degree and ratio of missing corners and edges, if the manufacturer's equipment is too old, there will be appearance of missing corners and edges on the brick, in the construction and use process, it will increase the difficulty of construction, and reduce the lining service life.   High aluminum bricks in the case of different brick types, the price will also change, depending on the degree of abnormity, if too heavy, too large, too thin, too abnormity of the brick type, will invisibly increase the overall price of high aluminum bricks. For example, a 5kg brick and a ton of bricks will increase the price of thousands of dollars in the mold part.   The number of high aluminum bricks in determining the direction of the price, if you only need one, two pieces bricks of the special part, only the mold item will increase the cost of thousands, so in the process of buying products can not only look at the price, also should attention at indicators and different brick type conditions and order quantities. Price comparisons cannot be generalized.

Rotary kiln products have cement, white ash, zinc smelting rotary kiln, as well as alumina, nickel and other rotary kiln. The proportion of rotary kiln used for firing ceramics is not very large.   Ceramic rotary kiln is also divided into three types: one is the rotary kiln for firing oilfield proppant ceramics, the second is the rotary kiln for shale ceramics, and then the rotary kiln for sludge ceramics, but the rotary kiln of these three materials is generally not large.   The oil field proppant ceramic is used in rotary kiln, temperature is 1400℃, the burning belt is generally selected special phosphate brick (body density is 2.85-2.9 can be used), and the phosphate brick of composite material can be used, and the burning belt is preferably not less than 25 meters. The transition zone can be made of ordinary phosphate bricks with a body density of 2.65. Corundum mullite castable can be used at the kiln entrance.   The temperature of the rotary kiln for smelting rock ceramics is generally about 1300℃, and 2.8 body dense special phosphate bricks can be used in the firing belt, and 2.65 body dense phosphate bricks can also be used in high aluminum bricks in the transition belt. If the fuel is not natural gas, rice husks or other waste products are used as fuel, it is best to use phosphate bricks, and try not to choose high aluminum bricks.   Sludge ceramic with rotary kiln, the temperature is not high at 900℃, the whole kiln length can use 2.65 body dense ordinary phosphate brick, because this material is fired in the rotary kiln, the temperature is low and no corrosion, the whole kiln can also use three-level high aluminum brick or clay brick.   As for the refractory brick type, the brick type closest to the size can be calculated according to the size of the kiln diameter, no special provisions are required. If the brick type is designed as a fan-shaped phosphate brick, at the end of the kiln, the brick type with a thickness of 80/70 thickness and two rings of the same length and width can be squeezed at the kiln mouth. If the vertical brick is selected, each ring needs two kinds of slotted bricks of thickness and the amount of each ring is squeezed.   In short, no matter using what kind of brick type of the phosphate brick and high aluminum brick, it must be fixed with the lock joint steel plate again when reviewing the kiln.

The lining of the molten iron tank is made of firebrick in different materials, such as clay brick, high-aluminum brick, low-porosity brick. And about the three cans, mainly use aluminum silicon carbide carbon brick.   The cycle is different according to firebrick material. Under normal circumstances, the use of clay bricks is more, but although the cost of clay bricks is low, the shortest number of uses is between 300-500 times, if the use of high aluminum bricks or low porosity bricks, the number of uses is 600-800 times, if the use of aluminum silicon carbide carbon bricks, the number of cycles is 1200-1400 times.   In addition, there are all the use of refractory castable can lining. The use of refractory castables is strong in air tightness, but there must be a special birthware, and a special baking device, the early cost will be high, and there must be a certain cost for making birthware and baking device. The use of refractory castables is also based on different quality, the service cycle is also different.   There is also a mixture of the two, the mixing scheme is the use of low porosity brick or aluminum silicon carbide carbon brick on the tank wall, the permanent layer of the tank bottom or the working layer are used refractory castable, this mixed use has its advantages, that is, when the tank bottom maintenance, you can save the lining of the permanent layer, the old lining can be used to reduce production costs. And the old lining is not like the low porosity brick bottom, which needs to be levelled before making the tank bottom lining, and when the castable makes the tank bottom lining, what kind of situation can be delayed and then used as castable.   If the lining of the tank all use aluminum silicon carbide carbon bricks, the permanent layer of the bottom of the tank is also mostly used refractory castable, the working layer is selected circular brick, and the wall of the tank is laid with various types of aluminum silicon carbide bricks, because according to the design of a variety of brick types, the entire lining will not be wrong, and the service cycle of the tank lining will be relatively extended.

Silicon manganese alloy is mainly used as an intermediate material for the deoxidizer and alloying agent of steel production, and is also the main raw material for the production of low carbon ferromanganese. Its consumption accounts for the second place in electric furnace ferroalloy products. Silicon-manganese alloys with carbon content below 1.9% are semi-finished products for the production of medium and low carbon ferromanganese and electrosilicon-thermal metal manganese. Silicon and manganese in silicon manganese alloy, strong affinity with oxygen, in the use of silicon manganese alloy in steelmaking, the resulting deoxidation products MnSiO3 and MnSiO4 melting are 1270℃ and 1327℃ respectively, with low melting point, large particles, easy to float, good deoxidation effect and other advantages. Under the same conditions, using manganese or silicon deoxidation alone, the burn loss rate is 46% and 37%, respectively, while using silicon manganese alloy deoxidation, the burn loss rate of both is 29%. Therefore, it has been widely used in steelmaking, and its output growth rate is higher than the average growth rate of ferroalloy, becoming an indispensable composite deoxidizer and alloy addition agent in the iron and steel industry. Calcium carbide furnace is the main equipment for producing calcium carbide. Calcium carbide furnace is a mineral heat furnace, the main raw material coke and limestone according to a certain ratio of requirements after mixing by electrode arc smelting reaction to produce calcium carbide (calcium carbide). Calcium carbide is produced in a calcium carbide furnace by melting the charge due to the high temperature emitted by the electric arc. Due to the reaction temperature of up to 2000℃ or more, such a high temperature, the general refractory is difficult to withstand. Therefore, the volume of the furnace body must be greater than the reaction space, that is, a layer of charge should be retained between the reaction zone and the lining to protect the lining. There are many shapes of the furnace body, including round, oval, square and rectangular. From the thermodynamic point of view, circular furnace is more advantageous. In fact, the choice of furnace shape is mainly determined by the arrangement of electrode positions and the installation position of carbon monoxide extraction equipment. It can be said that most of today's calcium carbide furnaces are circular furnaces, and very few use other shapes. The size of the reaction space in the furnace is determined by the size of the electrode, the distance and the arc range. The distance of the circular electrode is directly proportional to its diameter. The diameter of the electrode varies with the capacity of the furnace. The electrode diameter is determined by the current density it allows. The current of the electrode is determined by the transformer capacity. The final conclusion is that the size of the furnace body depends on the capacity of its transformer. Calcium carbide is produced in the furnace due to the melting reaction of the charge due to the high temperature emitted by the electric arc. Due to the reaction temperature of up to 2000℃ or more, such a high temperature, the general refractory is difficult to withstand. So the volume of the furnace must be greater than the reaction space. That is to say, a layer of charge should be retained between the reaction zone and the lining to protect the lining. The size of the reaction space in the furnace is determined by the size of the electrode, the distance and the arc range. The distance of the circular electrode is directly proportional to its diameter. The diameter of the electrode varies with the capacity of the furnace. The electrode diameter is determined by the current density it allows. The current of the electrode is determined by the transformer capacity. The final conclusion is that the size of the furnace body depends on the capacity of its transformer. The size of the furnace and the distance between the electrodes are very important. When the size is selected appropriately, the current flows mostly from the electrode end through the reaction and melting layer to the bottom of the furnace. At this time, the operation of the calcium carbide furnace is very smooth. Otherwise, a large amount of current flows from one electrode through the charge interdiffusion layer and the preheating layer to the other electrode. In this way, the electrode can not go deep into the furnace, the furnace bottom temperature is reduced, the three phases in the furnace are not easy to smooth, the calcium carbide flow is difficult, and the operation of the calcium carbide furnace is deteriorated, which is very unfavorable to production. The following is a brief introduction to the structure of the furnace body and the furnace door (1) The requirements of the furnace shell for the furnace shell :① the strength of the furnace body should be able to meet the severe expansion of the furnace lining caused by heating, and adapt to the requirements of the furnace lining expansion and contraction; ② In the case of meeting the strength requirements, we should strive to save materials and reduce weight; (3) Convenient manufacturing, if necessary, the possibility of packaging and transportation should be considered. (2) Filling layer: Usually the furnace wall brick lining is mostly wet masonry, and it expands when heated, so a layer of asbestos plate (or slag wool or dry sand) should be filled between the refractory brick and the iron shell. This layer is called the filling layer, also known as the buffer layer. The thickness of this layer depends on the size of the furnace, the masonry method and the nature of the refractory, which is generally 50 to 100 mm. (3) Firebrick lining: six layers of firebrick are laid above the filling layer, and the thickness is about 450~500 mm. The wall of the furnace is laid with two layers of refractory bricks to the top of the furnace. Generally, clay refractory bricks are used, and there are two methods of building refractory bricks: dry building and wet building. The wet laying method adopts 70% refractory clinker powder, 30% refractory raw material powder, and water mixing masonry. The brick seam should not be greater than 3 mm. Dry laying method has higher technical requirements, so the dry laying method is mostly used on the large capacity calcium carbide furnace, and the furnace wall is wet laying method. (4) Carbon brick lining: above the refractory brick layer, the thickness of the carbon brick layer varies according to the capacity of the calcium carbide furnace, the small capacity is 400~800 mm, the medium capacity is 800~1200 mm, and the large capacity is 1200~1500 mm. The masonry methods of carbon brick layer are divided into two kinds: coarse seam method and fine seam method. The rough seam method is to leave 30~50 mm brick cracks between bricks and bricks. The thick seam paste is heated into a paste, filled between the brick cracks, and then heated and tamped with a special tool and a pneumatic tool with a wind pressure of 3 to 7 kg /2 cm. The upper and lower brick seams should be staggered. Between the carbon brick and the fire brick, between the carbon brick and the top surface of the carbon brick layer should also be filled with a thick 50~100 mm thick seam paste. The fine seam method is to process carbon bricks into a plane with relatively high precision on the planer in advance. And pre-assembled in the processing plant, the tolerance size of each carbon brick is required to be ±1 mm. When laying on the calcium carbide furnace, the bricks and bricks are filled with melted fine seam paste, requiring that the brick seam is not greater than 2 mm. The fine seam method is the better of these two methods. However, the processing amount is large, so this method is generally only used on large capacity calcium carbide furnaces. It is easy to make coarse seam paste, but because of the volatiles volatilization during production, the holes between the brick cracks are easy to appear, and the permeability to prevent ferrosilicon is poor. In the large-capacity calcium carbide furnace, the brick lining at the lower end of the furnace wall is also made of carbon bricks, and the carbon brick between this layer and the carbon brick at the bottom of the furnace is also filled with a thin seam paste, the carbon brick is about 900 mm high and 400 mm thick. Corundum bricks are used near the furnace door to prevent oxidation of carbon bricks.

Refractory cement is also known as high temperature cement, high aluminum cement, aluminate cement, etc., natural high quality bauxite and high quality lime as raw materials, according to a certain proportion, through high temperature sintering (or through electric furnace melting) and mature material, aluminate as the main component of the clinker, and then ground into fine powder, made with fire resistance of hydraulic cementing material, known as refractory cement. The refractoriness of refractory cement is not less than 1580 degrees Celsius, and the main mineral phase is calcium aluminate (CA) and calcium aluminate (CA2).   Refractory cement is widely used in the refractory industry, especially in amorphous refractory materials, as a major hydraulic binder, with good high temperature resistance, stable setting time, high strength characteristics, Often we take the initial setting time, final setting time, 6-hour flexural strength, 24-hour flexural strength, 72-hour flexural strength, 6-hour compressive strength, 24-hour compressive strength, 72-hour compressive strength, etc. as an important basis for judging whether a cement is qualified.   The main chemical composition of refractory cement is aluminum oxide and calcium oxide, but in the application process of refractory industry, calcium oxide is a material in some sense, so the addition of refractory cement in amorphous refractory material is crucial, such as some low cement castable, it is necessary to strictly control the addition of refractory cement, usually 1%-3%. However, there are some rich cement castables, and the addition of refractory cement of these castables is usually between 10% and 20%. For different castables, different conditions of use, the type of refractory cement selected is different, of course, the amount of addition is naturally different.   Excellent quality refractory cement plays a vital role in the use of amorphous refractory materials, inferior products directly determine whether the castable can be used normally, but now some bad businesses, in order to reduce costs to maximize profits, use unqualified raw materials, reduce the content of refractory cement aluminum oxide, The initial setting time and final setting time are seriously inconsistent with the national standards, the folding strength and compressive strength are greatly reduced, and some businesses in order to achieve chemical indicators, add other substances (laundry detergent, building cement, etc.) to increase the content of aluminum oxide, although the chemical indicators can meet the national standards, but the mineral phase in refractory cement does not meet the standards. The bending strength and compressive strength do not meet the requirements, resulting in safety production accidents, so the selection of refractory cement has an important position in the amorphous refractory material.

The actual use effect of high aluminum bricks in the furnace lining is related to the quality of high aluminum bricks, and the quality is related to the price, so the key to the use effect depends on the price selected.   At present, the high aluminum brick on the market, in fact, there are many kinds of quality, why say there are many kinds of quality, manufacturers are produced according to the price, even if the use of the physical and chemical indicators set by the manufacturer, it is only a reference to the main index, to meet the main index, the price of high natural quality is good, and the messy market price the product quality is fixed at the price of the use effect.   The market is messy and the price is lower. Caused by the current resistance of some small and medium-sized enterprises in order to survive, have to price as the main line of production, because of the reason for survival, has messed with the lining temperature, atmosphere and reasonable selection of the principle, should choose the quality range of the price is too high, can not be traded. The deal is the lowest bid, so to win the bid for the purpose of survival. As a result, the quality of high aluminum bricks appears in countless grades. It doesn't appear as level three, level two, level one, or super. It is the aluminum content, body density, strength, load softening temperature, porosity in a variety of conditions to produce a variety of high quality aluminum bricks. By analogy, the second and third levels are also produced with different indicators, or only the main indicators, if all meet the national standard requirements, the price is far from the same. In this way, the index and price of high aluminum bricks have become a disordered product, and different quality products have appeared.   There are many kinds of high aluminum bricks in the first level, there are many kinds of quality of secondary high aluminum bricks, and three kinds are even more, so the quality of high aluminum bricks on the market at present can not set a unified price, only to see the price of quality in the maintenance of the production market and use situation.   In use, can not only listen to the quality of high aluminum bricks, can not use the quality of high aluminum bricks, at present the most is the aluminum content and body density to set the price of high aluminum bricks, in this regard, the actual use of high aluminum bricks can only be seen by the price of the effect. Can not be determined by the level and reasonable quality.

Low cement castable is a castable with a small amount of high aluminum cement.   The amount of cement added is small, in order to reduce the calcium content to avoid affecting the later strength, and the current manufacturers on the market have basically canceled the high amount of high-aluminum cement as a binder. The castables used are basically low-cement castables. Low cement castable has less cement addition, low calcium content and low water addition in site construction. The castable added water is low and the water is discharged quickly, and the later use strength is high, thus increasing the service cycle of the castable.   But no matter any kind of product, laboratory and actual use, there will be a certain difference, the region, weather, technology are the key links of the difference, if the region is different weather temperature there will be a difference, the temperature is also an important issue to consider the construction of castable, there is the technical difference of the construction personnel, do not understand the situation of the construction, It will also affect the service life of castable. Under normal circumstances, the amount of water added in the laboratory in actual use, there will be a deviation of about 2%, if the site according to the manufacturer's instructions to add water, still can not meet the flow of castable and initial coagulation requirements, first depends on the storage time of castable, if the storage time is more than 6 months, Then the binder separately equipped in the original ratio can be replaced before water is added to stir, and then construction is carried out. If it does not exceed the storage time, it depends on the temperature difference, if the temperature is too low, it is necessary to find a way to adjust the temperature between 5-30 degrees Celsius in the construction site.   If the time and temperature are available, and the amount of water added is more than 2%, it is necessary to consider whether the silica fume in the binder is damp, if the damp low cement castable will lack fluidity and need to be replaced before use.   In short, if the water addition of low cement castable site construction is greater than about 2%, it is necessary to solve the problem according to above situations.

Zinc volatilization kiln belongs to dynamic kiln, the kiln is in the running state of high temperature and continuous rolling, the physical and chemical reaction in the lining is intense and complex, the kiln lining is seriously worn, so the selection of refractory bricks in the lining should be very careful.   Zinc volatilization kiln body lining volume is large, will easily cause cylinder deformation; better use the bricks with reasonable design and the select suitable materials of firebrick; if the refractory brick have many joints, it will be easy to be eroded by slag, so should use dry brick construction; In addition, the kiln lining will be subjected to the combined influence of mechanical erosion and reduction atmosphere, and the erosion rate of the lining refractory will be very fast. Choose the corrosion resistance, wear-resistant material refractory brick is the premise, clay brick erosion is the fastest, magnesia brick, magnesia aluminum brick, chromium slag brick and magnesia chrome chrome brick erosion is slower.   In recent years, the special phosphate brick developed by the manufacturer of phosphate brick, means the phosphate brick with a body density of more than 2.9, the use effect is also quite good, but the use effect of magnesium aluminum chromium brick on the volatile kiln is also quite good, the difference from the two materials of refractory brick is that one is chemically combined brick, one is magnesia refractory brick, and another difference is about the price. The price of special phosphate brick is still lower than magnesium aluminum chrome brick. So the use of special phosphate bricks has more advantage.     If you choose magnesia-aluminum chrome brick, it is completely OK, its service cycle is long, the replacement frequency is low, if from the price, the special phosphate brick cost is low, it is also a good choice for high temperature zone lining. At present, there are more special phosphate bricks on the market.     Compare the using condition of high-aluminum bricks and ordinary phosphate bricks, In terms of market usage ratio, there are more ordinary phosphate bricks, if special phosphate bricks are used in the high-temperate zone, they are made of the same material as high-temperate zone bricks, the kiln lining atmosphere is consistent, and phosphate bricks are wear-resistant than high-aluminum bricks, the service cycle is relatively longer.

The appearance of the color presented by the clay castable has nothing to do with its intrinsic quality.   Clay castable is the low grade castable and it’s used in furnace linings at temperatures below 1200℃. Its color is related to the silicon powder added, the color of silica fume is uncontrollable, because there are many factors determining the color, the color is also unstable, if the color is strict, be sure to clearly state, so as to avoid unnecessary disputes.   The color of micro-silica powder mainly has white, gray, gray, gray black, black and so on. There are so many colors, mainly due to the production of alloy products of raw materials and processes determined, so each factory produced silica fume must be unique, in a certain aspect must be different.   Microsilica powder is an essential raw material in refractory castable. The flow value of castable can be increased by adding silica powder to castable. Silicon powder particle size is small, spherical particles, extremely easy to enter the tiny gap of castable, and the addition of silicon powder has a good water reduction effect, but also can improve the density of refractory castable, reduce the porosity, so as to make the strength of refractory castable better.   It’s unscientific to judge the quality of clay castable only from the appearance color. The silicon powder purchased by different manufacturers in different batches will have different color, but it has nothing to do with the quality of the clay castable.   The quality of clay castable has a great relationship with the amount of water added, setting time, strength and baking. If too much water is added during construction is the key factor affecting its quality, because too much water is added and the setting time is long, the later drainage process will have a certain impact, if the baking temperature is too fast, or the baking time is too short, it is the key to affect the quality of castable.   Therefore, the quality of clay castable is related to the production process ratio, construction water, setting time, and baking, but has nothing to do with the appearance color.

There are two kinds of carbon ramming paste: hot ramming paste and cold ramming paste. Hot ramming paste and cold ramming carbon materials are amorphous refractory materials composed of powder-grained refractory materials and binders. Cold ramming carbon materials are generally recommended.   Before ramming, the carbon ramming material must be broken and heated. The heating temperature is determined according to the uniform mixing temperature of the finished material. If there is no hard block in the heated carbon material, it can be laid and rammed. Use a hot hammer when ramming, and the material temperature is not lower than 70℃. When using hot stamping, the hammer head should be heated dark red, and the wind pressure should not be less than 0.5MPa. The upper and lower layers should be staggered at a certain Angle, and the ramming should be carried out continuously, so as to prevent stratification. "Shave" or brush the adhesive on the surface of each strip before spreading and ramming. When ramming, it is necessary to press a half hammer or a third of the hammer in a zigzag back and forth ramming 2-3 times.   When ramming the cold ramming paste, due to product process upgrading, no heating material is needed, and the construction does not need to stir, the material can be directly poured into the use part, manual or mechanical method of construction, the ramming material is also a hammer press half hammer way of ramming, but it should be noted that the thickness of each ramming can not exceed 100mm. Ramming compaction (reference compression ratio of 40-45%), if you need to increase the thickness, you can lay a second layer of ramming, but before laying the surface of the upper layer must be brushed, so that the upper and lower layers are combined with dense, the wind pressure during ramming and the wind pressure of hot stamping, can not be less than 0.5Mpa.   Carbon ramming material is mainly used for the gap between the furnace bottom carbon brick and the furnace bottom seal plate, or the gap between the furnace cylinder carbon brick and the cooling wall, as well as the leveling above the center line of the furnace bottom water cooling pipe and the filling of the cooling wall, filled with every corner and very small gaps, to achieve the requirements of no leakage of hot metal and gas.   The biggest difference between hot ramming and cold ramming of carbon ramming paste is that cold stamping has changed the old process method of traditional hot stamping, the working conditions and the lining performance has been improved.

Phosphate brick and high aluminum brick can be both used in the lining of lime kiln, phosphate brick is more suitable for the calcined zone than high aluminum brick.   Lime kiln is divided into vertical kiln and rotary kiln. At present, there are many vertical kiln tools on the market. Vertical kiln is generally used with high aluminum brick, clay brick and phosphate brick as the lining. However, if it is a rotary kiln, all phosphate bricks are used, low temperature belt with phosphate wear-resistant bricks, and high temperature zone with special phosphate bricks. Because the phosphate wear-resistant brick is alkaline atmosphere inside the kiln lining, the atmosphere is consistent with the lime, and the lime activity is good under the condition of the same gas field.   However, the transition zone is also used with high-aluminum refractory bricks, and the shaft kiln lining is also lined with clay bricks and high-aluminum bricks. The cost of high-aluminum refractory bricks is relatively lower than that of phosphate, but according to the use cycle, high-aluminum bricks are not as long as phosphate refractory bricks in the lime kiln lining. The lining material of shaft kiln lime kiln also depends on the region and the habit of the user. Some manufacturers use high-aluminum bricks, while some manufacturers use phosphate refractory bricks, which has no standard provisions. The lining is made according to the requirements of the user.   If from the view of technical point, phosphate wear-resistant bricks are more suitable than high-aluminum bricks for use in lime kiln lining, the main reason is that the use period is long, and the atmosphere is similar to the activity of the lime fired better.   In short, it’s no matter to use the phosphate bricks or high aluminum bricks, should notice that phosphate bricks are more suitable for use in lime kiln lining. If it is a rotary kiln, the whole kiln lining with phosphate bricks will be better.

PA80 refractory glue mainly application between bricks and bricks in the case of high temperature connection material, in a broad sense, can also be listed as high temperature refractory mortar, PA80 refractory glue and ordinary refractory mortar whether in quality and price, are very different.   The most difference between the two is the difference in the use of temperature areas, the general static industrial kiln lining construction can be ordinary refractory mortar, or phosphate refractory mortar, and the dynamic kiln lining is best to use PA80 refractory glue, because of the dynamic mechanical pressure and kiln stress, to prevent the brick drop out of the rotation process.   There are also a variety of ordinary refractory mortar, all according to the quality of the use of refractory bricks with the same material of joint refractory mortar, refractory mortar is divided into clay and high aluminum, silicon carbide, silicon, magnesium and other different series, are joint materials of masonry refractory bricks of different materials.   PA80 refractory glue is the use of specific binder and powder, powder and ordinary clay ratio has a great change, ordinary mud is generally 160-180 purpose powder and clay preparation. The PA80 refractory glue is made of powder, add ultrafine powder, and add a variety of special binders to boil, boil the glue with a bucket alone, the use of high temperature effect is remarkable.   The adhesion of refractory mortar is very important. Poor bonding will affect the bonding of firebrick joints and reduce the service life of firebrick. Ordinary refractory mortar and PA80 refractory glue must have dynamic fluidity and plasticity. There is no fluidity and adhesion, the joints between bricks and bricks during construction will not be tight, and the phenomenon of falling bricks will occur at low temperatures.   The thermal expansion or shrinkage of PA80 adhesive is better than that of ordinary refractory mortar, and it will not separate the refractory bricks or cause the clay layer to break. Integrity and rigor and unity work better. The adhesion of ordinary refractory mortar is good in the middle and low temperature area, and the strength is good at low temperature, while the PA80 adhesive will increase with the increase of temperature, and the strength of brick integration will become denser with the increase of temperature.   PA80 refractory glue and refractory mortar are selected according to the temperature and position of the static and dynamic kiln lining, and the different materials of the firebrick.

What kind of refractory castable is suitable for the 1300℃ furnace lining? it is based on the different lining atmosphere of different furnace types, no matter what material is selected, the ultimate purpose is to save energy and reduce consumption, to achieve the use effect and long service cycle.   Before choosing, we must firstly consider the fuel used by the furnace, the raw material medium of the fired product, and the corrosiveness degree and nature of the raw material composition, is it acidic or alkaline? In addition, there are external factors to consider the furnace type, whether there is wind speed, mechanical stress caused by erosion wear, and then the combustion mode.   The furnace temperature of 1300℃ is the direct contact temperature of the flame, not the fire resistance temperature, the definition of the fire resistance and the use of temperature is very important, under normal circumstances, the selection of high aluminum castable can be 1300℃ furnace temperature, the current use of high aluminum castable are basically using low cement class, but if the erosion is serious, it is necessary to according to the nature of erosion, Choose acid or alkaline material that is resistant to erosion. If it is acid erosion, can choose water glass binder or phosphate bonded castable, if it is alkaline erosion can choose high abrasive resistance and magnesium castable, high abrasive resistance plus silicon carbide, can resist erosion and wear. The selection of magnesium material should pay attention to the water and wind pressure of the furnace lining.   After selecting and using high aluminum castable, the construction process is also very important, because the selected high aluminum castable is also divided into different quality levels, if the early condensation is too fast, it may be unreasonable control ratio of binder and micro-powder, if the amount of cement is too large, not only the problem of fast condensation, but also lead to the late strength of high aluminum castable will be affected.   If the high aluminum castable condenses too slowly, the construction temperature should be considered, and the amount of water should be controlled when adding water. When the temperature is low, the drinking water should be heated to 30℃, and the material should be mixed and stirred before use. If it sets in 40 minutes. Then baking in accordance with a reasonable baking system can fully ensure the service life of high aluminum castable.

  The firing temperature of the brick process between the high strength alkali brick and fire clay brick is the same, but the the raw material process is not the same, the sintering temperature of the sintering time is not the same. High-strength alkali-resistant brick has strong alkali resistance, while clay brick is a slightly acidic product with strong resistance to acid erosion. Two kinds of refractory bricks are completely used in different atmospheres, alkali-resistant bricks are mostly used in cement rotary kilns, and fire clay brick have a wide range of use.   High-strength alkali-resistant brick need to add a certain proportion of high-voltage electric porcelain, silica, bauxite particles and powder after stirring, mechanical pressing, and then sintered at a certain temperature. The alkali resistance and strength of alkali-resistant brick can be improved by adding proper proportion of electric porcelain. With the addition of 20% of high-voltage electric porcelain and 10% of waste silica brick powder or silica powder, the high-strength alkali-resistant brick will have high strength, low porosity, thermal shock resistance, alkali resistance and fatigue resistance, which can better meet the needs of use.   The fire clay brick is made by bauxite particle grading, clay powder preparation, forming by the high pressure molding machine and then through high temperature sintering, The fire clay brick are mainly made of mullite, cristobalite and glass phase, their content determines the properties of fire clay brick. The composition and impurity content of clays is vary greatly from different producing areas. The phase composition of fire clay brick has a wide range of changes, and the current production of fire clay brick on the market has a part of recycling bricks, and the fluctuation range is relatively stable.   The high-strength alkali-resistant bricks are used in cement rotary preheater, calciner and tertiary air pipe, etc. These parts require high-strength alkali-resistant bricks with high strength, low porosity, good thermal shock resistance and excellent alkali resistance. The fire clay brick are suitable for a variety of industrial furnace linings, which are wider use than alkali-resistant bricks, and the using quantity proportion is also large.

Low cement castable and traditional castable is very different, mainly in the difference between the middle and final strength, the traditional castable in the middle strength is not good, but low cement castable is far better than the traditional refractory castable, not only because the cement content is low, and have less calcium content, but also the use of ultrafine powder technology, so that the castable is in a reasonable proportion of particles distribution. Moreover, the final strength and middle strength of castable also are further improved.   Compared with traditional refractory castable, low cement castable has higher density, lower porosity and higher curing strength at room temperature. At the same time, it has good volume stability, the volume shrinks after drying and calcination. The high strength and low cement material in the low cement castable is prepared by using pure calcium aluminate cement as the binder. The maximum use temperature of high strength castable reaches 1600℃, and it has good wear resistance at high temperature. High strength and low cement castables are suitable for use in all kinds of kiln linings with high temperature and strong erosion.   The low cement material with fused white corundum as aggregate is called low cement corundum castable, corundum low cement material has high mechanical strength, erosion resistance and abrasion resistance, the highest use temperature reaches 1700℃, low cement corundum castable is suitable for more than 1400℃, impact abrasion serious large cement kiln mouth, multi-barrel cooling machine elbow and other lining parts used. It is also suitable for use with all parts of the kiln lining above 1400℃.     Traditional refractory castables are made of refractory particles and powders, as well as high aluminum cement. The particle gradation of the aggregate part is not as fine as the low cement material. Cement particles are also coarse, and the proportion of cement added is large, the amount of water added during construction is also large. In addition, the amount of cement is large and the particles are not graded, so that the cement material can not be completely hydrated, especially at 800℃, there is basically no strength, so the performance of traditional castable is not as good as low cement castable.

The chimney lining is made of light weight acid-resistant castable, which has strong air tightness, and does not require light and heavy layers. The two-layer material construction reduces the thickness of the lining and improves the thermal insulation performance.   The traditional chimney lining selection of materials, under normal circumstances with acid-resistant brick and acid-resistant mortar masonry, and thermal insulation castable as insulation layer. However, the air tightness of masonry is not good because of the uneven vertical ash joints of acid-resistant masonry bricks. The insulation may also corrode the outer wall. In addition, the combination between acid-resistant bricks and bricks is not tight, which will also cause corrosive smoke to penetrate the masonry, and the double-layer masonry construction of thermal insulation castable and lined brick will also bring great inconvenience to the construction of the chimney.   If the chimney lining is made of light weight acid resistant castable, the heat insulation castable is combined with the acid resistant brick double lining layer. The acid-resistant castable with strong corrosion resistance, good heat insulation and high strength combined with light cement is used to make a mixed acid-resistant castable lining by casting, so that the heat insulation and anti-corrosion properties can achieve the use effect.   The light weight acid-resistant castable is composed of expanded rock particles, floating beads, adhesive and curing agent, the binder is sodium silicate or potassium silicate solution, the curing agent is ammonium phosphate, and then the acid-resistant castable is stirred into a semi-lightweight component with a specific gravity of 1.5 body dense. During the construction, the lightweight acid-resistant castable is poured into the template for vibration molding, and the initial setting and stripping are dried naturally. It has good resistance to sulfuric acid corrosion and can meet the requirements of chimney acid resistant lining.   The cementing agent used in the light weight acid-resistant castable is stable while the compressive strength is not reduced, and a small amount of volumetric expansion reactants are generated in the material to fill the tiny pores, which improves the compactness of the castable and makes the chimney liner more integrated with air tightness.

The working zone of cement rotary kiln is divided into drying zone, pre-tropical zone, decomposition zone, exothermic reaction zone (transition zone), firing zone and cooling zone.   In the traditional cement rotary kiln, the gas temperature in the drying zone is 250-400℃, the gas temperature in the pre-tropical zone is 450-800℃, the gas temperature in the decomposition zone is 1000-1400℃, the gas temperature in the exothermic reaction zone is 1400-1600℃, the gas temperature in the firing zone is 1700℃, and the temperature in the cooling zone is 1100-1300℃.   At the back of the cement rotary kiln, the length of the kiln mouth is about 1 meter, wear-resistant castable can be selected, but it must have a certain degree of alkaline resistance. The castable area from 10D to the rear kiln entrance can use anti-spalling high-alumina bricks; The 7D-10D section of the rotary kiln can use silmo brick or Silmo red brick; Section 5D-7D is a transitional zone, which can use magnesia-aluminum spinel brick; The 6D-7D section can also use Silmo brick or Silmo red brick;   The 0.6D-5D section of the cement rotary kiln is the firing zone, and this section is the high temperature zone, then the basic refractory bricks are used, including directly bonded magnesia-chromium brick, iron-aluminum spinel brick, magnesia-iron spinel brick, low-aluminum zirconia-magnesia-aluminum spinel brick, magnesia-iron-aluminum spinel brick, etc., among which the direct-bonded magnesia-chromium brick has the most cost-effective. If there are environmental protection requirements, magnesia spinel brick and aluminum spinel brick can be preferred; If white cement is produced, magnesia-aluminum spinel bricks with low aluminum and zirconium content can be used. When there are certain thermal shock requirements, magnesia dolomite brick containing zirconium can also be used; Magnesia dolomite brick can also be used for the more stable firing zone of the kiln skin, but remember that the dolomite brick must be used for the stable zone of the kiln skin.   The 0.8m-0.6D section of the cement rotary kiln is a cooling belt, which can use silica brick or high wear-resistant brick.   The 0-0.8m section of the cement kiln, that is, the front kiln and the coal injection nozzle can use high-grade refractory castable containing silicon carbide or magnesia-aluminum spinel castable. Under normal circumstances, the diameter and length of cement kiln have a direct impact on the daily output. 60 meters *4 meters kiln, is designed 2000-2500 tons daily output. 72 meters *4.8 meters kiln, is designed 5000 tons daily output, (the current domestic output is 5800 to 6300 tons of daily output). 7-8 m *96 m kiln, is designed 12,000 tons daily output. 74 m *5 m kiln, is designed 6000-7000 tons daily output.

What kind of furnace lining is suitable to use phosphate brick?   Phosphate brick is most suitable for use in white ash kiln, zinc kiln lining, can be used for high temperature zone and transition zone. If it is a white-ash rotary kiln, the entire kiln lining can use phosphate bricks, but it is the use of high density bricks in the high temperature zone, and the use of low density bricks in the transition zone.   Phosphate brick is bonded with phosphoric acid solution, belongs to the low-temperature chemical bonding refractory brick, the use of raw materials are bauxite clinker and phosphoric acid, through the trapped material, and then the use of press, high pressure molding, 550℃-600℃ low temperature sintering.   Phosphate refractory brick has good wear resistance, can be divided into wear-resistant brick, composite brick and other different body dense products, phosphate brick after several product upgrades, from the traditional chemical bonded phosphate brick, upgraded to the compound chemical bonded brick, the traditional product is the load softening temperature is low, reburning shrinkage. According to the actual use, some manufacturers add a certain proportion of silicon carbide in the raw material to make the phosphate brick more wear resistant, and the load softening temperature is high and corrosion resistance. It is even combined with lightweight materials to make thermal insulation and use one of the firebricks, so that the kiln lining temperature is slow, the shell temperature is low, and the service life of the kiln shell is extended at the same time, but also save fuel and reduce production costs.   Phosphate refractory brick on the basis of continuous optimization, there are high-load soft brick, corundum mullite brick, phosphate and light material composite brick on the market today, silicon corundum brick is based on the actual use of new process composite brick suitable for kiln use, in order to meet the white ash industry, zinc smelting industry different needs of furnace lining.   The use of phosphate bricks is not as large as the use of high-aluminum bricks, but it is a rare ideal material for use in white ash and zinc smelting kiln lining, because the atmosphere of phosphate bricks is close to that of white ash lining, and the white ash activity is good. The zinc smelting industry uses phosphate bricks, which have good wear resistance and strong slag erosion resistance.

The corundum brick is a kind of refractory brick with alumina content greater than 85%, corundum brick is divided into sintered and fused corundum brick, and chrome corundum refractory brick is added to corundum Cr2O3, after high temperature molding, high temperature sintering of high-grade refractory brick, chrome corundum refractory brick is also divided into fused cast chromium, sintered chrome corundum refractory brick.   The differences between the two kind of bricks:   The difference in high temperature resistance:   The refractoriness of chrome corundum brick is greater than 1790℃ and the load softening temperature is greater than 1700℃, the use temperature of corundum refractory brick is 1600℃, and the high temperature performance of chrome corundum refractory brick is better than that of pure corundum brick.   The difference in compressive strength:   The compressive strength of corundum refractory brick is 70-100MPa, and the compressive strength of chrome corundum brick is greater than 150MPa at room temperature, which is significantly higher than that of corundum brick. Al2O3-Cr2O3 solid solution is formed between particles and particles, between particles and fine powder, and between fine powder and fine powder, and the solid solution will connect the particles and fine powder together to greatly improve the strength of refractory bricks.     Thermal shock stability:   The thermal shock stability of chrome corundum refractory brick decreases with the increase of Cr2O3 content, that is, the thermal shock stability of chrome corundum brick with low Cr2O3 content is better than that of brick with high Cr2O3 content. Under normal circumstances, the Cr2O3 content of chrome corundum brick is between 12% and 20%; In particular, the AKZ chrome-corundum brick produced by adding a small amount of phase change additive has better thermal shock stability.   The resistance to slag erosion:   Corundum refractory brick is seriously eroded by slag, the slag will all penetrate into the brick, and along the internal pores of the brick into the surface, the surface of the brick becomes brown; Chrome corundum brick is almost not corroded by slag, the boundary between the inner hole edge and the residue is clear, and the slag penetrates little into the brick. The chemical corrosion and permeability of chromium-corundum refractory brick against gasification slag are better than those of corundum refractory brick.     Chrome corundum brick is usually used in glass kiln lining, hot metal pretreatment device, waste incinerator, gasifier lining and so on. Corundum brick is used in petrochemical and fertilizer industry cracking, conversion furnace, metallurgical industry steelmaking furnace, blast furnace and other high temperature kiln lining. Both products have their own advantages, but chrome corundum brick is more resistant to high temperature and erosion than corundum refractory brick. Corundum refractory brick is cheaper than chrome corundum refractory brick, suitable temperature, in order to reduce production costs, choose corundum refractory brick used in the right location and the right temperature, is also a reasonable choice.  

The refractory ramming material is an amorphous refractory material constructed in the form of ramming. The raw materials used in the ramming material and refractory castable are partly the same, but the density is relatively lower than that of castable, and the water added during construction is less than that of castable.   The process of refractory ramming material is composed of granular material and binder and other groups, mainly by the way of strong ramming construction. Ramming material can also be made of composite, with silicon carbide, graphite, electric calcined anthracite as raw materials, and castable to use the same micro-powder technology, adding fused cement or composite resin as the binder mixing composed of loose materials. Under normal circumstances, its role is to fill the gap between the furnace cooling equipment and the masonry or the masonry screed layer is used as a filling material.   The ramming material has good chemical stability, corrosion resistance, wear resistance, spalling resistance, heat shock resistance. Refractory ramming material ramming lining, low moisture content, knot dense, better performance than the same material refractory castable. If it is acidic ramming material with sodium silicate, ethyl silicate, silica gel and other bonding agents, dry ramming material with borate, alkaline ramming material commonly used magnesium chloride salt and sulfate;   After the refractory ramming material is rammed and formed, it can be disassembled and baked after self-hardening to a considerable strength; Containing thermoplastic carbon binder, after cooling after considerable strength and then demoulding, can also be cooled with a die for sintering.   The advantage of refractory ramming material is that it can be pounded on the spot in the form of ramming, the equipment uses air pick or mechanical ramming, the amount of material is less or the use of unimportant parts, and it can also be tied by hand. However, the disadvantage of refractory ramming material is that the construction speed is faster than that of refractory castable, and the labor intensity is greater than that of castable.

The process of dry barrier refractory is made of clay clinker as refractory aggregate, and the third grade high aluminum clinker is processed into different granular aggregate and powder, which is processed by micro-powder technology and bonding agent.   Dry material is mainly used in the aluminum electrolytic cell to play an anti-penetration role, in the electrolytic aluminum production process, the tank lining will be eroded by crcrite, and steam and aluminum liquid will also penetrate the aluminum solution through the carbon brick seam to the side wall of the refractory brick, insulation brick, and will penetrate through the carbon cathode at the bottom of the tank into the heat insulation layer, resulting in greatly reduced life of the aluminum electrolytic cell.   The dry material is selected according to the design of the electrolytic cell, and the material should be selected to ensure that the internal temperature of the carbon cathode material is greater than 850 ° C, because NaF will crystallize below 850 ° C, causing the volume expansion of the carbon cathode and the expansion of the carbon brick, reducing the service life. The best way is to choose a good thermal insulation brick as the heat insulation layer, and use dry barrier refractory between the carbon brick and the heat insulation layer as the barrier layer to prevent the penetration of harmful substances such as NaF.     The selection of dry barrier refractory should be m(AL2O3)/m(SiO2) greater than 0.9, in order to inhibit the penetration of Na and NaF. The infiltrated Na and NaF can react with Al2O3-sio2 refractory materials to produce nepheline (Na2O· Al2O3-2sio2), blocking the porosity and preventing the continued penetration of Na and NaF.   The role of dry barrier refractory is used between the carbon brick and the heat insulation layer on the side wall of the aluminum electrolytic cell, which can prevent the penetration of Na and NaF and other substances, and protect the heat insulation layer. The dry material is used directly on the heat insulation layer at the bottom of the tank. Construction thickness is 100~150mm. To determine the anti-seepage effect of the dry impermeable material, the crucible is heated to 950℃ in the electric furnace, and the sealed crucible is naturally cooled to room temperature with the furnace, the crucible is removed, the profile is cut for observation and analysis, and the remaining height H2 after the reaction of the dry barrier refractory and crolyte is measured, and the penetration depth (H1-H2) is calculated. The essence is the height of the reaction layer, that is, the permeability resistance of the impermeable material.  

The low porosity high alumina brick has low porosity and strong corrosion resistance, low creep high alumina brick is used in different conditions of furnace lining.   Low creep brick has high refractoriness, high softening temperature under load, low creep rate, and good thermal shock stability and chemical stability when used in furnace lining.   Low creep high alumina brick creep rate of 0.1-0.4%. When used at high temperatures, the deformation of creep bricks is very small, and the bulk density of this brick is high, and the strength and wear resistance are also increased. Can greatly contribute to the overall stability of the kiln. The apparent porosity of low porosity bricks is usually between 12-20%. The pore distribution inside the brick of low porosity brick is moderate, which helps to improve the stability of the brick.   Low creep high alumina brick has high load softening, strong thermal shock resistance, and can withstand rapid temperature change and multiple thermal shock cycles in the kiln. The corrosion resistance of low creep high aluminum bricks can also resist the erosion of many chemicals. In high temperature environment, it has certain corrosion resistance to alkali metals, sulfur, chlorine, etc.   Although the main raw material of these two kinds of high alumina bricks is high bauxite, although the sintering temperature and the same press to press, but the process ratio is not the same, low porosity bricks need to add burnt gems to adjust the porosity, increase the corrosion resistance, low creep bricks need to add red monolitic stone or mullite to adjust the creep rate. Only in the use of different lining, according to the needs of the manufacturer and the process adjustment of high temperature sintering.   Although these two are the category of high aluminum brick series, the use and the added raw material composition are not the same, and the price has changed, because the price of raw materials makes it different. In short, low porosity high aluminum bricks and low creep high aluminum bricks are the same, are the raw materials of high bauxite, the difference is that the performance is different.

The coke oven door is frequently opened during production, the surface temperature is high, and the coke temperature changes greatly. Cordierite brick and clay brick are used in the lining of traditional coke oven door in China, but the service cycle is not long.   The reason is that the product is complex in the coking process of the coke oven door, and the chemical erosion of the product is serious, which diffuses into the interior of the brick through the apparent porosity of the brick, diffuses and destroys the lattice structure of the brick, reduces the performance of the brick, and reduces the service cycle. The temperature change of coke oven door is large, and the sudden heating and cooling lead to the surface crack of lining brick, and also cause the corner damage of refractory brick.   If the coke oven door uses refractory castable, the body density should not be too large. Because the large furnace door is too heavy, the thermal conductivity is high when it is opened frequently. However, the use of lightweight castable, low thermal conductivity, small thermal expansion coefficient and elastic modulus, good thermal shock resistance and other characteristics, but the strength is not good, the apparent porosity is large, can not meet the demand. If the cordierite material is used as castable, cordierite has high strength and strong acid gas erosion resistance, but the price is expensive, the masonry requirements are higher, and the replacement of local damage is more difficult.   In addition, during the use of the coke oven, the tar will firmly adhere to the lining surface, and the formed carbon layer will be thick, which will cause the furnace door to be closed loosely. If the carbon deposit is cleaned up, the mechanical force will accelerate the early damage of the furnace door lining bricks. In recent years, refractory castable blocks have been used in the door lining of large volume coke oven. The material is made of clay and fused quartz composite castable; Because of the combination of this composite property, the refractory castable has strong thermal shock stability, and can withstand the thermal shock and frequent opening of the furnace door in the process of coke oven production. Moreover, fused quartz has a strong ability to resist acid gas erosion and resist carbon formation.   The use of clay and fused quartz composite castable to make precast blocks, clay material is cheap, high strength, in the manufacture of molding module or the whole casting, the production process is simple, and the use is more convenient. The introduction of fused quartz with very low coefficient of thermal expansion into the clay has the double effect of reducing the coefficient of thermal expansion and toughening the micro-crack, and the thermal shock resistance will be increased. It is fully adapted to the temperature of frequently opening the furnace door under acidic high temperature. In addition, the volume density and thermal conductivity of fused quartz are low, the molten quartz is introduced into the clay material, the thermal conductivity of the castable is low, the weight of the furnace door is appropriate, and the performance of the coke oven door is fully met.   While the properties of composite refractory castable can be used, it can be made into prefabricated blocks, which is convenient for construction and has a long service cycle. Therefore, the use of clay and fused quartz composite refractory castable is most suitable for the use of coke oven doors.

After the castable is added with retarding agent, it cannot be used without fluidity, because the castable has difficulty condensing without fluidity, which seriously affects the strength of the castable.   As for the castable manufacturers, under normal circumstances, according to the weather throughout the year, they will add coagulant in winter, and add retarder in summer to adjust the condensation of castable. Because below 5℃ and above 33℃ will affect the solidification time of castable. The most suitable temperature for the construction of castable is 15-25 ° C, if it is a fast-drying explosion-proof castable, below 15°C must be added to the binder for adjustment intervention.   If the setting time is too long or the fluidity is directly lost after the addition of retarder in summer, one is that the retarder is added to excess, and the other is that the ratio of coarse particles and fine powders is unreasonable in the castable process ratio. If the ratio of coarse particles and fine powder is unreasonable, the castable will be separated and stratified when mixed with water during construction.   If the fluidity of retarding agent is reduced in the laboratory, this batch of castable can not be used, the main reason is that the amount of retarding agent is too large. In addition, when the manufacturer is producing, it is necessary to control the process ratio during production. To eliminate the adverse possibility that the product may occur.   For Castables, especially in summer or winter, only the fluidity measured in the laboratory can not be used as the final basis. Because the size of castable aggregate is different and the temperature during construction is different, the effect of use is also different. It must be based on the temperature and actual use of the phenomenon.   So the fluidity of castable is very important, without the fluidity of the site there is no way to carry out construction.

High alumina brick is a kind of middle grade Fire brick among the stereotyped products of refractory materials. It belongs to neutral refractory materials and is used in the lining of industrial kilns.   The quality of high alumina bricks is distinguished by different aluminum content and body density, and the fire resistance of high alumina bricks reaches 1790 ℃. It is also possible to add different ingredients of raw materials to produce different materials and composite refractory bricks. By adding a certain proportion of phosphoric acid and sintering at low temperature, phosphate bricks can be produced. By adding a certain proportion of silicon carbide, high-temperature sintering can produce silicon molybdenum bricks or silicon carbide bricks. Adding Andalusite and sillimanite of different proportions can produce low creep high alumina bricks. These three Fire brick also distinguish different grades and quality of Fire brick according to different contents and bulk densities.   From the perspective of high aluminum bricks alone, if the aluminum content exceeds 48%, they can be called high aluminum bricks. There are also high aluminum bricks with different aluminum contents of 55%, 65%, 75%, 80%, and 85%, which can be used in furnace lining at different temperatures. However, high alumina bricks are not suitable for use in acidic or alkaline furnace linings. The composition of high alumina bricks is aluminum, and the production technology is to add high alumina particles in different proportions to high alumina powder, which is formed under high pressure and sintered at high temperature. High strength and good thermal shock stability.   In particular, composite materials of different materials are used more widely. Corundum, silicon carbide, silicon nitride, Andalusite, Kyanite, sillimanite, magnesium powder and other materials can be used in special furnace linings in different fields. The scope of use of high alumina bricks has been further expanded.   High alumina bricks are the most widely used and widely used refractory product among refractory materials. They can be used in various furnace linings in industries such as metallurgy, building materials, environmental protection, power, glass, etc. They are most suitable for use at high temperatures of 1250-1500 ℃.

Fire clay bricks quality is different indifferent area in China due to the local raw materials level, for example of the clay bricks in Henan, the aluminum content is high and more purity, the body is dense, and the use effect is almost the same as the general three-level high aluminum bricks.   Fire clay brick is one of the lowest grade products in the refractory brick series, but its wide use and low price are the biggest advantages of the product. In China, because of the raw materials of clay bricks, the indicators and use effects of clay bricks produced by provinces are very different. Including the price, there is also a big difference.   The clay bricks produced in Henan have high aluminum content and high volume density due to local raw materials and production processes. The price is relatively higher than that of a clay brick in Shandong and Hebei, and the use effect is also longer than the use cycle in Shandong and Hebei. Henan's clay brick color is yellow and white, the aluminum content is between 52-56%, the single weight of the standard brick is between 3.6-3.65kg, and the ton price is relatively several hundred yuan higher than Shandong and Hebei.   The clay area in Shandong is yellow and red, the aluminum content is about 40-45%, and the single weight of the standard brick is between 3.3-3.5kg, but due to the local material reasons in Shandong, the porosity will be about 3-4% lower than the clay brick in Henan. The sintering temperature is about 30℃ lower than that of clay bricks in Henan area.   The clay brick in Hebei is a deep dark red color, the single weight is between 3.3-3.5kg, the aluminum content is between 40-45%, the single weight of the standard brick is between 3.4-3.5kg, but generally no more than 3.5kg. The difference in sintering temperature and Henan is about 20 °C, the ton price will be 50-100 yuan higher than Shandong brick, and the porosity is higher than Henan and Shandong.   The three places have the lowest ton price of clay bricks in Shandong, the porosity is low, and the ton price of brick in Henan is the highest, but the body density and aluminum content are the highest, and the service cycle is the longest.     The use of clay bricks depends on the actual situation of the use of furnace lining, no matter which region of clay bricks, according to the actual use of selected can not only look at the ton price.  

High alumina brick and anti-spalling high alumina brick compared, anti-spalling high alumina brick is made of high bauxite and zircon as raw materials, high strength, chemical corrosion resistance, low thermal expansion coefficient, low thermal conductivity. And high alumina brick is made of high bauxite as raw material, chemical corrosion resistance is not as good as anti-spalling high alumina brick, mainly anti-spalling high alumina brick than high alumina brick thermal shock stability.   High alumina brick has strong resistance to spalling, corrosion resistance to potassium, sodium, sulfur, chlorine and alkaline salt, low thermal conductivity and other properties. It is an ideal material for cement kiln transition zone and decomposition zone. Its remarkable characteristics are good heat resistance and shock resistance and strong ability to adapt to the environment. It is mainly used in rotary preheater or calciner and grate cooler.   There is also a difference in the firing temperature between high-alumina brick and anti-spalling high-alumina brick. The high temperature firing temperature of high-alumina brick is 30-50℃ higher than that of high-alumina brick. The thermal conductivity of high-alumina brick is lower than that of high-alumina brick, and the load softening temperature is higher. However, the high alumina brick can not enter the large cement rotary dry kiln, because the service life is too low, repair, stop kiln frequently form considerable energy loss and economic loss. More importantly, it can not overcome the inherent shortcomings of use in harsh parts.   The refractoriness of high alumina firebrick is mainly affected by the content of Al2O3, and the refractoriness increases with the increase of the content of Al2O3. High aluminum brick is close to neutral refractory material, can resist the erosion of acidic slag and alkaline slag, because it contains SiO2, so the ability of alkali slag resistance than acid slag ability than high aluminum brick spalling is weaker. High alumina brick is mainly used in the lining of blast furnace, hot blast furnace, electric furnace top, blast furnace, reflector furnace and rotary kiln.   In addition, high alumina brick is also widely used as open furnace regenerative lattice brick, plug head for gating system, water brick and so on. In short, whether the use of spalling high alumina brick or high alumina refractory brick, according to the furnace erosion situation and temperature.

Electric furnace top in more than 20 years ago, in foreign countries, the use of silicon brick as the top material, but in China, generally are high aluminum brick or prefabricated block to do the top.   Because the top of electric arc furnace is affected by the sudden change of temperature, slag injection, gas erosion and thermal radiation, the top refractory materials must have good thermal shock stability, corrosion resistance and high refractories. Firebrick for furnace cover is an evolutionary process of silicon brick, high alumina brick, alkaline brick and amorphous refractory (large prefabricated block). Because of the poor thermal shock resistance of silicon brick, the use of furnace top only about 60 times, in China as early as 20 years ago has not used silicon brick for the top of electric furnace. Alkaline firebrick is also some of its own shortcomings, can not resist the ultra-cold, extremely hot temperature changes under ultra-high power, silicon brick and alkaline brick has been replaced by a high alumina brick, corundum brick, high alumina precast block, castable. In particular, the water-cooled furnace cover only uses refractory materials in the central part of the furnace cover. The use of molded bricks to build the furnace takes time, and the ash joint between bricks and bricks is not strict, which will make the stress distribution uneven and reduce the service life of the top protection.   In recent years, large prefabricated blocks made of high strength castables have been used more than 1000 times to build furnace tops. In China, the top brick is generally made of high aluminum, which is used in 300-400 furnace times. Five to six times longer than silicon bricks, but small stoves are suitable for high alumina bricks and corundum castables.   At present, the number of large prefabricated blocks used on the top of electric furnace in China is increasing, because according to the shape of the top, the electrode hole is set aside for the whole furnace cover, which greatly reduces the complexity of the construction link. And the service life of the first grade high aluminum brick more than 2 times the service life. However, the price of prefabricated integrated top is relatively high. Some small top stoves use high quality aluminum bricks to do top stoves because of financial problems. With the development of amorphous refractory castables, ultra-low cement castables have been successfully applied to electric furnace tops. The use of ultra-low cement castable in the triangle area improves the service life a lot. The whole furnace top is prefabricated, the life of the furnace top has reached 600 times, and the small furnace cover has reached more than 1000 times.   General electric furnace is intermittent production, rapid cooling and rapid heating temperature is frequent, the use of silicon brick furnace top that increases the number of replacement, but also increases the production cost. So the top of the electric furnace is not suitable for the use of silicon brick.

Light insulation brick is divided into different materials, different body density. At present, the proportion of clay light brick will be more, if it is too high temperature insulation layer, must use suitable for different temperature insulation brick. If the temperature is 1000℃, choose clay insulation brick. If the temperature is 1300℃, high aluminum light insulation brick should be selected, if the temperature is above 1350℃ insulation layer, mullite insulation brick should be selected. There are some light kiln, lining the working layer is also selected light brick to reduce the weight of the kiln body, that is to choose alumina hollow brick. Whether clay, high alumina, mullite have different body density of 1.0, 1.2, 0.8, 0.6, the smaller the body density, the better the insulation effect. Alumina hollow ball insulation brick is 1.2, 1.0 body dense, but some of the furnace lining of special materials construction, or to choose a slightly higher strength insulation brick, because the body dense is too small, working layer of heavy brick will wear insulation brick in the process of use into pieces. The insulation effect is affected. Of course, the body density is different, the price is different, the smaller the body density of the insulation brick price is higher. Because the size of the body density is not the same thermal conductivity. The smaller the body density of the thermal insulation brick, the lower the thermal conductivity, the better the thermal insulation effect, so as to save the fuel during the use of the kiln body, reduce the production cost. And the smaller the body density, the lower the weight of the industrial kiln, the smaller the body density of the insulation brick, the higher the raw material price, the better the insulation effect, but the price will be higher, but the selection of light insulation layer in the process, but also consider the problem of strength, the smaller the body density of light insulation brick, the lower the strength, if the working layer of heavy brick body density, Or consider the body density of light brick, if the body density of low material insulation brick is too high, insulation effect is not good, it is necessary to choose high material insulation brick to do insulation layer, or heavy brick grinding insulation brick, insulation effect will be affected, and heavy brick with insulation layer broken, will move, the lining of the whole kiln will need to be replaced and repaired. But if the working layer uses alumina hollow ball brick, you do not need to consider the problem of too small body density, alumina hollow ball brick can play the role of insulation, but also can directly contact the flame. Reduce the trouble of insulation layer and heavy layer, can directly play the dual role of insulation and use. Therefore, the body density of light insulation brick is different, the insulation effect is different, and the selection is the most reasonable according to the temperature of the kiln.

In the process proportion of refractory castables, the aggregate plays a skeleton role in the castables. The amount of refractory aggregate is generally 60% - 70%, which can improve the strength and wear resistance of castables in use.   The process proportion of refractory castables is mainly aggregate, and then add 15%~25% of powder processed with the same quality as the aggregate, which can fill the aggregate gap and improve the fluidity of materials during construction. Then 6-12% of the binder is added to the castable. Good binding agent, ideal particle grading is that the gap caused by coarse aggregate is filled with fine aggregate, and the gap between them is filled with refractory powder to achieve the maximum bulk density, so as to obtain the best use performance.   Refractory aggregate is divided into coarse aggregate and fine aggregate. Generally, those with particle size greater than 5mm are called coarse aggregates; those with particle size less than 5mm and less than 0.09mm are called fine aggregates. The critical particle size of aggregate depends on the thickness of the lining. If the construction thickness is 30-50mm, 0-5mm aggregate is used. If the thickness is 100-200mm, 0-8mm and 0-10mm aggregate particles are used.   However, the ladle castable and refractory castable for iron trench are mostly made of 20mm - 25mm particles due to special use conditions. The critical particle size of refractory aggregate is different, and the purpose of use will also be different. When preparing refractory castables, the aggregate grain grading will be adjusted from time to time, that is, to meet the grain grading of the finished product and the overall performance of the product, and to consider the actual use of the lining.   In refractory castables, refractory aggregate and powder processed from bauxite clinker are mostly used. For alkaline or acidic furnace lining, aggregates made of siliceous materials and alkaline materials are used, and powders made of the same materials are used. The binder shall also be adjusted under different conditions, and the high-alumina cement in the binder shall also be adjusted. At the same time, the silica powder or aluminum oxide powder shall be adjusted to different degrees. The main purpose of adjustment is to improve the actual use.   For refractory castables used in some special parts, oxidation and construction conditions should also be considered, and different conditions should be adjusted to meet the use needs.

Hydration series of refractory castables, the drying process can be roughly divided into three stages.   The first stage is in the temperature from room temperature to 100 degrees Celsius, generally natural drying temperature is about 40 degrees Celsius. But the fastest dehydration temperature of hydrated refractory castable is 50-60℃.   As the temperature increases, the temperature at the solid-liquid interface reaches a boiling point, which is the beginning of the second stage. The temperature of the second stage is 100-170℃. Because a lot of water vapor is produced at this stage, the conduction of water vapor increases the rate of dehydration. At this stage, the castable billet will produce a certain amount of shrinkage from the surface to the inside, which will slow the steam discharge. Some of the hydrates have begun to dehydrate in the range of 100-170℃.   The temperature of the third stage of drying is within the range of 200-400℃. In this temperature range, it is mainly the dehydration of hydrate. In fact, there is a great correlation between the temperature rise rate and the dehydration rate. Under normal circumstances, the binder has calcium aluminate cement refractory castable, the actual removal process is very complex, when close to 100℃, there is free water, with the rise of temperature, the dehydration temperature of the raw material in the trichlorite and its gel is between 210-300℃, the real dehydration temperature of crystallizational water is about 530-550℃. That is to say, hydration refractory casting expected 550℃ dehydration will end.   In the process of dehydration, the relaxation strength of the castable structure decreases. Because there is a lot of water vapor discharge, there will be a lot of pressure in the body of refractory castable billet, and in the baking process, the temperature rises too fast, it is very easy to burst. In order to prevent cracks in the process of baking and drainage of castable, a certain proportion of explosion-proof fiber must be added during production, so as to facilitate the smooth discharge of water in the process of dehydration.   The drying and baking of refractory castable is a very important link. If the temperature rises too fast in the process of temperature rise, the refractory castable will burst and cannot be used normally.

  The rotary kiln is a steel cylinder lined with firebrick or castable. The most calcined products are in rotary kiln used in cement industry. In aluminum, copper, zinc, tin, nickel, tungsten, chromium and other metal rotary kiln has also been used. There are calcined lime and calcined magnesia, alumina spinel, bauxite, hard clay, rare earth, ceramite, incineration waste and other calcined materials of different rotary kilns, the firing temperature is also different, the highest temperature is 2000℃, the lowest is about 1000℃.    The working principle of rotary kiln is same, all are rotary kiln, kiln tail, kiln head, pre-tropical zone, firing belt, cooling belt, because of the rolling impact, friction, erosion of the burned materials, the selection of refractory materials are also different.   The lining of cement kiln is made of magnesia-alumina spinel brick, magnesia-iron alumina spinel brick and magnesia-alumina spinel brick. The lining of lime and dolomite kiln is made of phosphate brick, phosphate composite brick and magnesia aluminum spinel firebrick. There are also castable and prefabricated firebrick combination methods, and all castable casting methods as lining. The pellet rotary kiln uses high-aluminum brick or low-porosity firebrick, which can also be lined with castable. It can also use prefabricated firebrick and castable combination lining. In general, this method is used only after several kilns.   Zinc oxide kiln erosion is serious, frequent replacement, silicon corundum brick, that is, phosphate added to corundum and silicon carbide composite brick and clay refractory brick, a few manufacturers choose explosion-proof fiber wear-resistant castable and prefabricated brick, with anchor parts fixed, in the high temperature zone use effect is good.   Alumina rotary kiln or alkali sulfide rotary selection of anti-spalling high aluminum brick, the use effect is better; For burning petroleum coke, the combination of prefabricated composite brick with anchor nail and castable can also be used for lining. Chrome corundum brick or corundum mullite refractory brick is used as the lining of waste kiln which erodes refractory materials seriously. Castable masonry is lined with chrome corundum castable or corundum mullite castable.   Laterite nickel kiln, rotary kiln direct reduction production process of nickel iron, the use of microporous magnesium-aluminum-zirconium brick firebrick, the use effect is obvious.  

If furnace lining is one of the important parts of IF furnace, the life of IF furnace lining also has a great influence on the service life of IF furnace, so it is necessary to ensure the service time of IF furnace lining and improve the service life of IF furnace lining.   Here are the factors affecting lining life of intermediate frequency furnace:   1. Knotting process The knotting quality of the furnace lining will directly affect the service life of the intermediate frequency furnace, so the sand particle size is uniform when the furnace lining knotting, the coarse and fine particles do not produce segregation, and pay attention to the tight combination between the layer and the layer when feeding, so as to ensure the high density of the knotted furnace lining, the strength of the sintered layer, and the quality of the furnace lining.   2. Electric furnace capacity and furnace wall thickness Intermediate frequency furnace electric capacity, the greater the furnace wall of liquid metal under the static pressure will increase, the scouring effect of electromagnetic stirring force for furnace wall will also strengthen, if in pursuit of super pack, reduce the wall thickness, for those large electric furnace, the service life of furnace lining will be significantly reduced, so to select suitable for electric furnace capacity of furnace wall thickness, it can prolong the life time of the furnace wall.   3. Melting temperature If the molten metal melting temperature in the intermediate frequency furnace is too high, the corrosion of slag on the lining will be aggravated. Each kind of casting melting temperature has its requirements, to often observe and measure to find the appropriate melting temperature, do not blindly pursue high temperature, too high temperature will not only burn alloy, but also cause damage to the furnace lining.   4, Melting material For the furnace lining, when the furnace wall has not been sintered, smelting as far as possible to choose relatively clean metal materials, avoid which components are complex, rust, oil pollution more materials, especially oil-immersed waste iron filings. The material with low melting point and good fluidity will intensify the penetration of the furnace wall, and the material with high melting point needs higher melting temperature, which will affect the life of the furnace lining.   5. Smelting operation The wrong smelting operation will accelerate the wear of the lining, thus reducing the service life of the lining. Metal burden charging affects the burden in terms of melting speed, in order to speed up the melting furnace charge, charging requirements closely, but also to avoid burden bridging phenomenon occurring in the melting process, makes the lower part has molten metal overheating, intensifying metal suction loss of alloy elements, on the lining erosion, affect the service life of furnace lining.  

As we all know, induction furnace ramming material has a wide range of application, whether it is cast iron, cast steel, cast copper, nodular cast iron, gray iron, plain carbon steel, high manganese steel, stainless steel, special steel, alloy steel, iron alloy, alloy copper and other foundry, steelmaking, ironmaking plant will be used in induction furnace ramming material. There are many mistakes in the application of induction furnace ramming materials. For example, some customers think that white quartz sand should be used as the raw material for quartz sand, and some think that the finer the better, and some say that only powder is not needed. These are the induction furnace ramming materials do not understand the formation. After having a plenty of because used fine material, feel furnace age is pretty good, choose fine material all along so, and do not want to use relatively thick material. This is a myth. Now, the main demand for quartz sand raw materials is investigated by several factors, one is the content of silicon, but also the content of silica. Silica must be above 99%, the higher the fire resistance, the better.   Now many use red quartz sand, because the red quartz sand has high refractoriness, the general quartz refractoriness limit is 1760 degrees, and the red quartz refractoriness can reach 1750 degrees. White quartz sand refractoriness is generally in 1700 degrees. There is in addition to iron filings, in quartz processing when easy to mix iron, so in the production of induction furnace ramming material must be removed iron, otherwise easy to cause the phenomenon of furnace.   As for the ratio of quartz sand particles, the finer the better or the thicker the better. This should be done on a case-by-case basis. For example, it is a ton of electric furnace, so the selection of slightly coarse particles does not affect, the selection of fine points can also be. If it is 40 tons of induction furnace, 15 tons of induction furnace so the selection of very fine particles is not appropriate. The same one ton of electric furnace, coarse and fine particles can be, only the proportion of reasonable allocation can be. It's mostly a matter of habit. As the saying goes: three points of material seven points of use. No matter how good the data, if the oven is not good, the same furnace age is not high. Therefore, when we use it, in addition to the induction furnace ramming material should be bought by the appropriate manufacturer, the oven must be strictly executed in accordance with the instructions given by the manufacturer.

1. Feeding damage Feeding damage is due to the damage generated when feeding to the intermediate frequency furnace, mainly because some large raw materials did not pay attention to when adding, so that large raw materials from high to add, causing damage to the furnace lining. When feeding, pay attention to the height of the raw material falling, can avoid this damage, at the same time, when adding pieces of block material, need to pay attention to prevent the furnace lining to scratch.   2. Thermal shock damage Thermal shock damage is caused by thermal stress caused by improper use of furnace lining. If you do not continue to use the molten metal after it comes out of the oven, then the furnace temperature will drop. In the process of temperature drop, the lining thermal expansion and contraction as well as the quartz type reverse change, under the influence of these two effects, the lining sintering layer cracks, glaze warping, peeling and other damage. At this time, if the damaged sintering layer is damaged after restarting the intermediate frequency furnace, the service life of the furnace lining is reduced. Therefore, intermittent operations need to be avoided as much as possible. If the output of enterprises is lower, can adopt the method of day opening night stop production, where each in the last furnace to left a third of the liquid metal, low power heat preservation at night, then two days to continue to feed production, so to run than boiler stop two days remelting save electricity, but also can greatly prolong the service life of furnace lining, the comprehensive economic benefit is higher.   3. Chemical erosion (1) Molten iron erosion. Furnace lining is mainly corroded by carbon in molten iron, which occurs in the smelting of gray cast iron and nodular iron, especially in the smelting of nodular iron. (2) Waste residue erosion. CaO, SiO2 and MnO easily form slag with low melting point in scrap iron and steel. Therefore, we should pay attention to the cleanliness of raw materials when using. For the thin-walled waste with serious oxidation, it will produce more slag, so try to use less or not, and add less in each furnace. (3) refractory slag. The high melting point slag is caused by the aluminum in the raw material, which reacts with the SiO2 in the furnace lining to form mullite (3A12O3-2sio2). The melting point is 1850℃, so the aluminum in the raw material should be removed to avoid the formation of high melting point slag. (4) additives. The use of slag coagulants or flux in smelting operations will aggravate the erosion of the furnace lining and should be avoided as much as possible. (5) Carbon deposition. Carbon is deposited on the cold side of the furnace lining and even into the insulation layer. When the carbon deposition will cause the furnace body grounding leakage, and even coil sparks.

Dry material is dry vibrating material collectively, there are many called dry mixing, because its construction method is more than ramming, and called it dry ramming material.   This kind of dry material is in the dry state, the use of vibration or pounding method of construction and use, according to the material can be divided into just jade, silicon, silicon aluminum, magnesium and magnesium calcium and other types.   Dry material is mainly used in induction furnace, aluminum melting furnace, tundish and steelmaking electric furnace lining, dry ramming material in the construction, is to put the ramming material into the mold and permanent layer or the space between the furnace shell, after vibration ramming after baking and then use.   The working principle of dry ramming material is: after the completion of construction or after heating and baking, when the hot surface should form a certain combination and have a certain strength, the mold can be removed or not removed to let the steel die melt into the molten iron or molten steel.   If it is in the smelting process, the working face in contact with molten metal or slag will quickly form enough strength, or form a dense sintering layer resistant to slag and metal penetration. A loose and unsintered state remains behind the sintered layer. As the corroded sintered layer of furnace lining advances from inner wall to outer layer, the thickness of dispersed layer decreases gradually.   The role of unsintered loose layer is threefold. First, after a furnace service, the loose layer is still unwound, and it is very easy to fall off when the furnace is turned over. And there are thermal insulation effect, reduce the heat dissipation of furnace lining, reduce the sintering of loose layer. The third function is to prevent metal penetration.   Dry ramming material at the same time play the role of heat insulation and wear-resistant permeability is two contradictory points, heat insulation requires small accumulation density, high permeability requirements. Therefore, the production process should determine the proportion and granularity of dry ramming material according to the actual situation, but also pay attention to the choice of binder and burning aid and the influence of particle size on the ramming material.

The fire-resistant plastics used for boiler lining are different from those used for iron cement lining, because the fire-resistant plastics used for boiler lining are bonded with phosphoric acid, while the fire-resistant plastics used for hot metal lining are bonded with resin.   Boiler and furnace roof with refractory plastic, are all with a 3-0 and powder particles on the combination of using diluted phosphoric acid, phosphoric acid is a combination of material has to be trapped, if is urgent need, plastic manufacturers will direct some binder, did trapped in the transportation time is expected, and to use to join the rest of the binder, when using can be used directly. If the use period is long, the particles and powder are individually packaged, and the phosphoric acid binder is packaged in barrels. When adding part of the binder to the construction, the binder must be trapped for more than 16 hours before adding another binder for construction. So the way of production is different depending on the situation.   The refractory plastic used in hot metal packaging is combined with resin, without the need for trapped material. When construction, directly add the appropriate proportion, and is the direct use of diluted resin mixing. Because resin and phosphoric acid combined use methods are not the same, the price is also a lot of difference. The use of temperature is not the same, and the use of the effect is not the same.   Whether you dilute it with phosphoric acid or dilute it with resin. There is a certain proportion of aggregate and powder do raw materials, binding agent is also added in proportion, the difference is only the problem of trapped and not trapped materials and different prices. Of course, the temperature is also different. But the amount of refractory plastic used in hot metal packaging is not much, which plays a remedial role. Phosphoric acid combined with refractory plastic can also play the role of lining repair, can also be used in large areas of the use of the use of the layer.   These two kinds of fire-resistant plastic combined in different ways are different binding agents and different ways of adding. Construction ramming way is basically the same, but with different furnace lining different temperature.

The quality of refractory mortar, not only judging from the index. In the field construction has good construction performance, after baking enough strength and erosion resistance, is to judge the real quality of refractory mortar.   Refractory mortar and refractory brick, refractory castable is the same as the application of materials, not only to see the laboratory results or indicators, indicators are certain reference, but in the use and construction of the spread, is the most important. Refractory mortar in construction, are daub with spatula on the surface of firebrick of different materials, brick joints between firebrick, prevent slag erosion through brick joints into the interior of firebrick. Affect the service life of firebrick.   Usually, fire-resistant mortar in the production of finished, fire-resistant mortar manufacturers, will do a small test, is to use two pieces of standard brick refractory mortar on intermediate daub, surface rub moves back and forth until can't rub moves, adhesive, the longer this batch of refractory mortar spreadability is better, if you rub moves back and forth two condensation, this batch of refractory slurry wouldn't have to use, Because in the field construction personnel will not have time to operate, mortar has lost liquidity, it is impossible to carry out construction operations. If the number of rubbing is more than a dozen times, it means that this batch of mortar in the construction of the operation is not a problem.   Either high alumina refractory mortar or clay mortar can use this method. The rubbing test can also be carried out on the surface of two silica bricks if it is a silica mortar. Dry mortar, however, cannot be used in this way. Under normal circumstances, it is the same material of refractory bricks with the same material of refractory mortar.   If only from the aluminum content and indicators to determine the quality of refractory mortar, it is not absolute, sometimes the higher the aluminum content of mortar, but the site construction effect is not good, the reason is to consider the aluminum content alone, adding too little clay binder, mortar in the field construction no liquidity, can not be used.   Therefore, the quality of refractory mortar must have good construction performance, the strength after baking is the most important.

The lining of intermediate frequency furnace depends on the size of the furnace to decide whether to use castable or ramming material.   Under normal circumstances, the small furnace is 1 ton of intermediate frequency furnace will use castable, if it is a vacuum furnace is first made of castable crucible, after 1200℃ baking, directly into the furnace lining for use. And a little bigger furnace lining, such as 15 tons of medium frequency furnace, is to use refractory ramming material to do lining material.   The material of crucible castable is also the same as that of large-tonnage furnace lining ramming material, aluminum magnesium spinel castable. However, particles have a certain limit, and the particles of castable are between 0 and 3. The particle of ramming material is 0-5mm, the largest is 0-7mm. And refractory ramming material is ramming construction in the field. Because the amount of water added by ramming material is small, it has certain benefits for the lining baking of intermediate frequency furnace.   If small tonnage vacuum furnace lining with castable, it can also be constructed in the field, but there are not many manufacturers with such construction, because the furnace lining is small, it is difficult to cast. It is best to be in the castable manufacturer, directly cast into the crucible and furnace lining shape exactly the same, after barbecuing hair to use the manufacturer, directly into the lining for use. It works better that way.   Whether it is castable or ramming material, but also depends on the medium frequency furnace atmosphere of the material, if it is acidic lining to use acid material to do refractory ramming material, if it is neutral is to use plate corundum or white corundum made of jade ramming material. And if it is alkaline furnace lining, it is to use alkaline material to do ramming material.   Due to the use of intermediate frequency furnace is not sustainable, the ramming material made of alkaline material is not as good as neutral material in thermal shock. With the continuous improvement of actual use, aluminum magnesium spinel ramming material is used as lining. In this way, the problem of thermal shock is solved, and the atmosphere of the material is basically consistent with the lining. Such castables with alkaline lining atmosphere or refractory ramming are used more often.

On the definition of refractory materials, countries are not the same.   According to international standards, refractories are defined as non-metallic materials and products whose chemical and physical properties allow them to be used at high temperatures (without excluding the inclusion of a certain proportion of metals).   The American standard defines refractory as a nonmetallic material that, based on its chemical and physical properties, can be used to make structures and devices exposed to temperatures higher than 1000F(538 c).   Japanese standard will stipulate refractory materials: can be used in the temperature of more than 1500℃ shaped refractory materials and the highest use of the temperature of more than 800℃ shaped refractory materials, refractory mud and refractory heat insulation bricks.   China's standard for refractory materials follows IS0 standard, which stipulates that refractory materials refer to non-metallic materials with physical and chemical properties suitable for use at high temperatures, but does not exclude certain products that can contain a certain amount of metal materials.   As can be seen from the definition of refractory materials in the three countries above, the connotation and extension of refractory materials are not the same. Some specify the temperature, some don't. And their provisions of the use of the temperature is very far apart, but they also have in common, that is resistant material must be able to withstand the temperature of its damage.   Therefore, refractories are defined according to the most basic requirements of the environment in which they are used. However, with the progress of science and technology, the requirements of modern refractories have far exceeded the basic requirements. What is refractory material, to understand the requirements of refractory material.   The use environment of refractories is very complex, and different use environment puts forward different requirements for it. Comprehensive analysis of the use of environmental requirements for resistant materials. As well as for each specific use requirements, have the corresponding use performance of the material and corresponding.

The alkali and acidic chlorine content of the alkaline atmosphere lining will deeply penetrate the interior of the high-aluminum brick. Cause the use cycle is short, therefore, alkaline atmosphere under general circumstances do not use high aluminum brick lining.   The erosion of alkaline atmosphere will lead to transverse cracks in high-alumina brick, and loose foams will appear on the surface of high-alumina brick to 0-10mm thickness. It also causes the brick to expand and the alkaline components to deposit on the upper surface of the high-aluminum brick. The hot side of high - alumina brick is the use side will be more serious than the cold side erosion. If the use surface is seriously eroded, then it is bound to make the high aluminum brick service cycle is shortened.   And the content of silica in high-aluminum brick is higher than that of alkaline brick. The higher the content of silicon, the greater the amount of liquid phase, the more unsuitable for the use of alkaline atmosphere lining, excessive liquid phase makes the brick deformation, and the strength is also reduced. The existence of free silica in brick will increase the damage risk of brick.   Once the free silica in the high alumina brick is consumed, the internal crystal phase will be more seriously eroded. At the same time, mircanite and mullite in bricks will react directly to form zoisite, and further, it will cause destructive expansion. High-aluminum bricks used in alkaline atmosphere lining will have the possibility of sudden collapse of furnace lining.   High aluminum brick is the refractory material that belongs to neutral boundary to finalize the design product, use under neutral atmosphere commonly. If it is used in alkaline atmosphere, alkali erosion will cause the expansion and strength of the lining of the brick to decrease. When the indexes are reduced, the inner change of the brick will occur. After the inner change, the peeling of the lining of the brick will occur and even the lining will suddenly collapse, resulting in the normal use of the furnace lining.   Therefore, alkaline erosion atmosphere lining should not use high aluminum bricks. Choose alkalescent firebrick and alkalescent atmosphere are consistent, atmosphere is unified, and fight alkalescent firebrick use cycle is long, the change frequency that reduces lining also reduces productive investment.

Fluidized bed boiler chamber, cyclone separator, feeder, external bed and other parts. The lining structure is three layers, the first layer is insulation layer, the second layer is insulation layer, the third layer is working layer.   Cone section and straight section of cyclone separator are three-layer structure, the first layer is light insulation brick, the second layer is insulation firebrick and the third layer is heavy firebrick, the thickness of 350-400mm.   The refractory material of the returner is a three-layer structure, the first layer is insulated firebrick, the second layer is ultra-light castable and the third layer is low cement castable, the thickness is 400-430 mm.   Furnace temperature is high, is a layer of structure. In general, heavy corundum wear-resistant castable is used with a thickness of 150-200mm.   The external bed is a two-layer structure, the first layer is insulated firebrick, the second layer is low cement castable, thickness of 300-380mm.   The bottom ash cooler is a two-layer structure, the first layer is insulated firebrick, the second layer uses spray paint or low cement castable, thickness 200-410mm, there are also roller slag coolers.   Boiler of lining materials, refractory mortar joint must build by laying bricks or stones, refractory castable must strict control of water addition, completes the maintenance and baking, to ensure the normal start and stop of boiler furnace and the load change process, depending on the degree of erosion using the temperature of the parts, choose suitable lining materials, and construction personnel's technical level is the construction personnel should choose to have certain experience. Make the lining material reasonable construction.   In a word, there are many factors that affect the use effect of the lining of fluidized bed boiler, but it is necessary to insist on the quality of the lining material and the whole construction process control. Construction shall be carried out in strict accordance with the construction process of firebrick and castable used for lining.

The shape of the pores has an effect on the thermal conductivity of firebricks or castables. The thermal conductivity of refractories with more closed pores is less than that of those with more open pores. If the pores are cylindrical, the pores will increase, and if the pores exist in the firebrick or the interior of the castable is spherical, the thermal conductivity will decrease a lot. And powder and fiber materials affect the thermal conductivity of refractory materials, sintered firebrick will have less impact than castable, thermal conductivity is affected by the heat transfer of pores, if the shape of fiber material is vertical, the impact on the thermal conductivity will be small.   Temperature and gas pressure also affect the thermal conductivity of refractory materials, but the reasons are very complicated. When the gas pressure is large, the thermal conductivity will increase with the temperature. If the pressure is small, the thermal conductivity changes little as the temperature increases.   The size of pores has a certain influence on the relationship between thermal conductivity and temperature and pressure, and the influence of porosity and thermal conductivity-temperature and thermal conductivity-pressure and porosity are different. Under low pressure and low temperature, the influence of pressure on the thermal conductivity of firebricks is relatively weak. Under high temperature greater than 1200 degrees, the influence of pressure on the thermal conductivity of firebricks with high porosity is greater than that of low porosity.   In short, the thermal conductivity of firebrick and castable is closely related to its composition, structure and working conditions, and most of the firebrick or castable is thermodynamic non-equilibrium state, especially in the use of the composition and structure change, will affect the physical properties of firebrick or castable. Especially for refractory castable products, as well as prefabricated products without high temperature sintering, the influence on thermal conductivity is particularly prominent.

How is cementless castable bonded Cementless refractory castable is a high-grade castable, which is produced by composite ultra-fine powder technology or sol. Because there is no cement, the calcium content of the castable is less than 0.2%, and the low melt formed is very few, so the performance of the castable is better than that of the general low cement castable. The varieties of cementless castables include aluminum silicate, mullite, corundum, magnesium series and silicon carbide series. The setting and hardening of this kind of castable is through the coagulation and combination of ultra-fine powder, and the strength is obtained by the coagulation and combination. The admixture plays the same role as the low cement castable. Cementless castables use oxide ultrafine powder as binder, or silica sol and aluminum sol as binder. They can also be used in combination. For example, alumina ultrafine powder or silica ultrafine powder is used for corundum castable. Aluminum silicate castable uses silica ultrafine powder plus alumina ultrafine powder, or silica sol as binder. For example, the wear-resistant spray coating for blast furnace lining is the material combined with silica sol, and the application effect is good. The cementless castable is coagulated by adding and dispersing or dissolving the ultrafine powder or colloid in the castable, so that the castable has a certain fluidity. After stirring and vibration forming, the castable coagulating is added by adding the gel. Although the hardening process of cementless castable is slow, the strength increases with the increase of temperature. Aluminum silicate cementless castable will expand slightly after burning, and corundum will shrink, but it has excellent high temperature performance. The non cement refractory castable has low impurity content, and its fire resistance, corrosion resistance and high-temperature structural strength are better than those of Low Cement Castables. The raw material of this castable is used with high aluminum material and carbon containing material, and its application effect will be better.

Industrial furnace furnace shell temperature is high and low, the higher the temperature of the kiln skin temperature is higher, if you want to reduce the temperature of the kiln skin, we must improve the use of insulation materials, or thicker insulation layer.   Normally, insulation uses light clay brick and light fiber board, cotton, blanket more. But all are using fiber insulation materials do not use light clay brick, with light clay brick can not fiber insulation materials.   But if the kiln skin temperature requirements are low, it is necessary to do multi-layer insulation to reduce the degree of heat diffusion, reduce the temperature of the kiln skin.   Multi-layer insulation to do three layers, the first layer with 50mm thick light coating as the lining, the second layer with 50mm thick high purity fiberboard insulation, the third layer is made of 0.6 light clay brick body density as the lining insulation, so multi-layer insulation, the temperature of the kiln skin will be reduced a lot, under normal conditions of 1000℃ temperature, do three layers of insulation, The temperature of kiln skin will decrease by about 100℃.   After smearing the lining, the air tightness of the whole furnace lining is stronger and the heat dissipation speed is slowed down. Each layer of high purity fiberboard has a better heat reduction effect. In this way, the thickness of the entire insulation layer is 224mm. The thickening of the insulation layer slows down the heat speed, so that the heat will not be directly evacuated to the kiln skin through the kiln.   The temperature of the kiln skin is reduced a lot, while the air tightness is strong, the heat dissipation speed is slow, but also to ensure the internal temperature of the kiln lining, the internal temperature of the kiln lining lasts for a long time, but also to reduce the fuel problem of the heating up of the kiln body. Less fuel reduces the cost of production and use.   That is to say, with three layers of insulation daub, fiberboard, light clay brick to do the insulation layer, that is, reduce the temperature of the kiln skin, but also save fuel, it can be said that two birds with one stone to do the insulation method.

Bottom leveling material and filling material are not the same refractory castable Bottom leveling material and filling material may be the same refractory castable, or may not be the same, because some of the filling material is aggregate and powder directly dry into the firebrick brick joint. And some use castable to fill the gap after mixing firebrick.   At present, there are many manufacturers on the market, which use the same kind of castable, but the aggregate particle can not be too large, because the aggregate particle is too large to fill in, generally controlled at 0-6 particles. The bottom leveling material is either high aluminum castable or refractory concrete.   Refractory castables of the same material can be used if high aluminum castables are used.   However, if there is no bottom screener and only a filling material, there are also 0-6 aggregate particles, which can be made into a high aluminum castable combined with high aluminum cement. Can also be made into different grades according to the temperature of the firebrick layer, made to adapt to the temperature of the working layer castable. After adding water to stir, fill in the gap of firebrick to work, in order to increase the air tightness of furnace lining, so that the temperature inside the furnace is slow down, so that the fuel is saved, and the temperature outside the furnace is relatively low. At the same time also saves the production cost.   If at the same time with the bottom leveling and firebrick filling, it is completely possible to make the same refractory castable, that is, to make the bottom leveling, and fill the gap between the firebrick. The reason is that during construction, there is no need to exchange castable back and forth, and the temperature of the same furnace lining is only a little change. The construction of the same castable is convenient, and it also prevents the gas field from being different from the same castable.   Therefore, the filling of the leveling material is not absolute, but depends on the use of different furnace lining temperature and different gas field and customized into what material and grade of refractory castable. Can use the same kind, can also use the same material, different grades of castable.

The construction of castable for flue lining can be carried out after installation, or the lining can be constructed before installation. The temperature of the flue is not high, but the smoke and dust and acid erosion are very large, especially the heat exchanger should be washed with water, which brings great impact on the construction and use of the lining material. For the construction of the lining castable of the flue, 3mm gap should be left between each castable to set expansion joints. Castable construction is a piece of castable adjacent to the sealing material before the next piece of casting.   If it is installed after the completion of lining construction, relatively better. It is easy to construct the large diameter flue liner with castable. However, if the large diameter pipe is heavy, the lining construction will be carried out before installation, which will double the weight of the pipe, increase the installation risk and make it difficult to weld components. Therefore, the large diameter flue liner is suitable for construction after installation.   The construction of refractory castable for flue lining before installation is suitable for the construction of castable for small diameter flue lining because of its light weight. Construction before installation also reduces the difficulty of aerial work, castable is carried out on the ground, low labor intensity and high construction efficiency. The disadvantage is that the lining construction can not be carried out continuously, and the expansion joint is not easy to deal with.   The construction of castable for flue lining should pay attention to safety first, then the welding of anchor parts and the way of castable casting. For large-caliber flue, the anchor nails are welded first, then the anchor parts are painted, and then the construction is divided. The construction is divided into three and four valves after the construction of two valves within 180°, the pipeline is turned to 180°, and then the construction of three and four valves, if there is a insulation layer, the insulation layer of the insulation castable, and then the construction of wear-resistant castable working layer.   In addition, if the pipeline lining has two or two kinds of castable construction, it is also necessary to separate the construction of 4 pieces, but the construction of each piece can be stopped for 12 hours before the construction of the next piece, the first casting construction of the lower half, and then the flue is turned over on the ground, casting the other half.   If it is lined on the ground, the pipe opening should be corrected and deformation prevention measures should be taken. Prevent pipe opening deformation due to large or light weight in construction. During castable construction, the position that is easy to deform should not be constructed first, and the lining construction should be carried out on the dismantled position after the construction of other parts is completed.   For pipe elbow, expansion joint and valve, castable shall be constructed in sections, and expansion joints shall be reserved for pipe sections in horizontal and vertical directions. The position of the position is not high can be taken to support the inclined mold casting, and vibrating compaction, cut off the excess part along the tangent line. If the space is small and the construction joint position is high, the castable construction adopts flat port butt, and 3mm high temperature resistant ceramic fiber felt is clamped into the joint, and then group welding is carried out.

High aluminum bricks with the same aluminum content may not be of the same quality. Because the aluminum content of high aluminum brick is only one of the indicators to distinguish the quality, the same as the aluminum content, but also look at the volume density, the higher the volume density, the higher the density of high aluminum brick, the higher the wear resistance; But also look at the size of high aluminum brick and whether there are internal cracks; The size should be regulated by the national standard to expand or close the ruler range can be regarded as qualified. There are cracks, depending on whether it is lamellar or surface mesh cracks. If the surface of the high aluminum brick is just a mesh crack, it is caused by too high temperature or too fast drying in the drying process, which generally affects the internal use. If it is lamination, it will not work, because the internal structure has occurred fault, it can not be used. Although the aluminum content is the main index, but the load softening temperature of high aluminum brick is also very important, if the temperature of sintering is high, it means that the raw material is good and the internal quality is dense, and the load softening temperature is high. If the sintering temperature is low, the softening temperature under load is low. Volume density and softening temperature under load can best prove the quality of high aluminum bricks. Under normal circumstances, the softening temperature under load can not be seen or weighed out, and the volume density is the most intuitive can weigh the density of high aluminum brick, that is, the most direct judgment of the inner quality of high aluminum brick a method. The heavier the firebrick, the higher the volume density. And the user that a few not understand a situation very much, often can see color and aluminous content to judge the stand or fall of high aluminous brick quality only, it is unscientific. Some of the high-aluminum bricks are particularly beautiful in color and are very uniform, and the sizes are in a reasonable range. But the quality is light, this explains this batch of high aluminum brick is to use raw aluminum powder to adjust the color of the brick, and the intrinsic quality is not compared with cooked powder. Because the color of raw aluminum powder added to the brick looks good, but when used at high temperature, the wear resistance and high temperature resistance are not as good as the use effect of high aluminum brick produced by adding clinker. Therefore, to determine the quality of high aluminum brick and times, must look at the volume density of the softening temperature to determine the load.

The bonding modes of firebrick and castable can be divided into ceramic bonding, chemical bonding, hydration bonding, organic bonding and resin bonding.   The ceramic bond form is the bond produced by sintering or liquid phase formation at a certain temperature. This kind of combination exists in the fired products, the fired brick mostly belongs to the ceramic bonded refractory. There are direct bonded firebricks in ceramic bonded refractories, direct bonded bricks are sintered refractories connected by solid phase diffusion mechanism, direct bonded refractories are mainly magnesium-chrome firebricks, magnesium-chrome bricks in high purity is directly connected between magnesite and spinel, there is no mesophase.   However, with the development of microscope technology and material science, it is found that the particles are not really directly bonded, and there are often impurity concentration or lattice distortion areas at the bonding site. However, the term "direct binding" often appears in magnesia-chrome refractory materials, mostly in the literature of basic refractories.   Chemical bond is a bond formed by chemical reaction hardening at room temperature or higher, including inorganic or organic composite bond. This combination is often used in phosphate refractory bricks or prefabricated refractory bricks.   Hydration bond is formed by chemical reaction between fine powder and water at room temperature. Organic bond is a bond formed by hardening of organic or inorganic matter at room temperature or slightly higher temperature. This bond is often used in castables such as cement bonded castables. In fact, these two forms can be combined. Because the combination of water in castable is also very common. Resin combination is the refractory material containing resin is heated at a lower temperature, because of resin curing, carbonization, common in non-burning products. Such as mud without pressure.   Bitumen/tar bonding is produced by bitumen/tar bonding in pressed non-burning refractories, mainly used in carbonaceous refractories, such as anhydrous mortar, etc.   These categories are not absolute. In practical production and application, hydration bonding, organic bonding, resin bonding and bitumen/tar bonding all have chemical reactions to a certain extent in the bonding process. Resins combined with bitumen/tar can also be incorporated into organic bonds. These kinds of combination forms are based on a variety of artificial stage agent division.   In the manufacture of firebricks and castables, various combinations exist independently and sometimes simultaneously.

Gasifier lining atmosphere is different, the use of castable is also different. Zirconia series refractory castables are used for oxidizing atmosphere and silicon carbide series refractory castables are used for reducing atmosphere. Silicon carbide series castable have the advantages of corrosion resistance, high wear coefficient. It is very effective in reducing melting loss. Moreover, silicon carbide castables have the advantages of high thermal conductivity and good thermal shock resistance. It is best used in reducing atmosphere gasifier lining. The upper temperature of the gasifier is low, and the material is sprayed with high strength. Near the tuyere, due to the thermal decomposition of the residual solids, ash melting serious, and side wall parts are also used silicon carbide series of refractory castable. Furnace is oxidation atmosphere, will produce slag alkali erosion, the general use of al2o3-Cr2O3 series of refractory castable, but also useful castable containing chromium oxide properties, this castable slag resistance ability, good corrosion resistance. But the porosity will be higher. Will be in the furnace temperature fluctuation, caused by the thermal spalling or by the influence of slag infiltration, resulting in structural spalling, damaged lining. Also, chromium oxide is rarely used because of its toxic properties. The addition of zirconia castable can greatly improve the spalling resistance, and the effect of erosion resistance and slag resistance of castable is good. What kind of refractory castable is used for gasification furnace lining determines the service cycle and cost control. When choosing castable, the operating atmosphere and slag composition of the furnace should be carefully studied. To choose between silicon carbide castable or zirconia castable series. Because the furnace lining atmosphere is different, can not use the same series of refractory castable, after distinguish the atmosphere, choose the appropriate series of castable as lining, not only increase the use time of furnace lining, but also save the production cost.

In the traditional production of refractory castable, many people pay little attention to the content of sodium oxide in alumina powder, but the content of sodium oxide in alumina has a great influence on the performance of refractory castable. The final performance of the product is for the site construction effect and use effect. Because the high content of sodium oxide will increase the amount of low melt, it will have a great influence on the dispersion of mud, and on the construction performance and setting time of refractory castable. Because the dissolution of sodium oxide into the solution will shorten the hydration time of pure aluminum calcium cement and alumina slurry, the higher the content of sodium oxide in alumina, the greater the influence of powder surface area. At the same time, the formation of hydrate, the setting time and the properties and microstructure of castable body after solidification are affected to a certain extent. The activity, integrity and surface characteristics of alumina powder will have a certain influence on the construction performance of castable, resulting in the construction of condensation too fast or not. The particle size distribution of alumina powder also has great influence on the performance of refractory pouring material. The smaller the particle size, the larger the surface area. The more sodium oxide and other ions get into the solution. As a result, the service time or erosion resistance of refractory castable is reduced. The particle size distribution of alumina powder has great influence on the filling and packing degree of refractory castable. The particle size distribution of alumina powder can be divided into single-peak and multi-peak. The single bee distribution has only one peak value and only one mode particle size on the particle size distribution curve. Multimodal distribution means that there are two or more peaks on the circular line of the number diameter distribution, that is, there are two or more modal particle sizes. The larger the peak size distribution, the greater the bulk density of alumina powder, because smaller particles are more likely to fill the void formed by larger particles. Denser refractory castable and more resistant to erosion. The bulk density of alumina powder with single peak distribution is small. It is easier to obtain higher volume density of refractory powder by using alumina powder with multi-peak particle size distribution than by using single peak particle size distribution. The alumina powder with wider distribution has better filling ability and higher packing density. Therefore, the sodium content of alumina powder can not be high, otherwise it will affect the density of refractory castable.

Reasons for spalling of refractory castable used in calcium carbide furnace cover The biggest reason of spalling refractory castable used in calcium carbide furnace cover is the damage of anchor. Improper shape of anchor will cause damage to anchor first, which will cause castable to fall off. In addition, the quality of refractory castable and construction operation will also cause castable to fall off. The furnace cover of calcium carbide furnace is an important part to determine the gas efficiency of closed furnace. In the production and use, the furnace cover is easy to smoke, fire, by smoke and heat loss of airflow erosion serious. Therefore, the most important thing to pay attention to when using refractory castable for furnace cover is the shedding of castable. Calcium carbide furnace furnace cover installation of anchorage is very important, but the shape of the anchorage parts is top priority, will generally use V anchor pieces, but the anchoring piece bending of the loss, the most easily when welding anchor pieces must be of the anchorage bend or string it handle, the most scientific way is to fold bend flat spin distance, The distance of flat folding had better not be less than 20mm, so as to ensure the buffering in the most easy to wear, so that the use cycle of anchoring parts increases. The flat folding of the anchor can also be extended to 30mm. In this way, the service cycle can be lengthened. The flat folding of the V-type above should be lengthened, and then the flat folding of the upper part of the anchor should be painted twice, the thickness is 2mm, and the plastic cap can also be taken. Bolts shall be welded to 30 bolts per square before casting of refractory castable. The diameter shall not be greater than 6, and the thickness of refractory castable shall not be less than 150mm, but the castable shall use micropowder technology. In this way, less cement is added and the calcium content of refractory castable is low. In the construction, when the refractory castable is stirred, the amount of water should be added as little as possible to ensure the later use strength of the castable, so as to prevent the castable for the furnace cover from falling off.

The difference between silicon brick and semi-silicon brick Silica brick is refractory product with SiO2 content above 92%. The higher the content of SiO2 in silica raw materials, the higher the refractoriness of products, the ability of acid erosion resistance is very strong. Semi-silica brick is made of pyrophyllite as the main raw material, and its refractoriness is more than 1700℃. Good thermal shock resistance, can withstand the impact of steel slag and metal, and has a strong creep resistance. Silica brick belongs to a variety of acid refractory materials, has a strong resistance to acid slag or acid melt erosion ability, alkali erosion resistance is very poor, and the expansion coefficient of silica brick is very large. The volume of silica brick is stable between 300℃ and melting point. When heated to 1450℃, volume expansion of 1.5% ~ 2.2% will occur. The biggest disadvantage of silicon brick is poor thermal shock resistance and low refractoriness (generally 1690 ~ 1730℃), so its application scope is limited. A semi-silica brick made of waxy stone. There will be micro expansibility. Because of the mineral composition of wax stone, the lattice size of pyrophyllite in its crystal structure changes little when heated, so it shrinks when roasted, and sometimes expands slightly. In the process of high-temperature use of semi-silica brick, pyrophyllite reacts with acidic slag, forming a layer of glaze substance with high viscosity on the surface of semi-silica brick, preventing the infiltration of acidic slag into the brick, and the ability to resist the erosion of acidic slag is also quite good. The amount of silicon brick is large and the variety is large. It is mainly used in the carbonization chamber, combustion chamber and partition wall of coke oven and the kiln roof and kiln pool of glass kiln. There are also high temperature bearing parts of hot blast furnace, carbon baking furnace and other furnaces also use silica brick as lining. There are many kinds of silica brick, including silica brick for coke oven, silica brick for hot blast stove, silica brick for electric furnace, silica brick for glass kiln, etc. The use range and amount of semi-silica brick is not as large as silica brick, which is extremely limited. Although it can be used as the bottom lining of ladle, hot metal ladle lining and flue, the semi-silicon brick is seldom used because of the improvement of steel quality.

Alumina bubble insulation brick is made of alumina hollow ball and alumina powder as the main raw material, combined with other binder, after 1750 degrees high temperature firing. Belongs to a kind of super high temperature material energy-saving heat preservation material.   Alumina bubble is a new type of high temperature heat insulation material, it is made of industrial alumina smelting and blowing in the electric furnace, crystal form is A-al2o3 micro crystal. Alumina hollow ball as the main body, can be made into various shapes of products, the highest use temperature 1800℃, products of high mechanical strength, for the general lightweight products several times, and volume density is only half of corundum products. It is widely used in high and ultra-high temperature kilns such as gasifier in petrochemical industry, carbon black industrial reaction furnace and induction furnace in metallurgical industry, and has achieved very satisfactory energy saving effect.   For reducing the weight of the furnace body, reforming the structure, saving materials and energy, it will achieve obvious results.   Advantage: 1, High temperature: Can reach more than 1750 degrees, good thermal stability. Reburning wire change rate is small, longer use.   2, Optimize the structure, reduce the weight of the furnace body: Now the normal firebricks with high temperature resistant materials are heavy brick volume density of 2.6-3.0g/cm, but Alumina bubble insulation brick only 1.1-1.5g /cm, so in the same cubic meter volume, the use of Alumina bubble insulation brick can reduce 1.1-1.9 tons of weight.   3, Save materials: To achieve the same service temperature, such as the use of heavy brick price and Alumina bubble insulation brick price, but also need considerable insulation refractory. If the use of Alumina bubble insulation brick, per cubic meter can save 1.1-1.9 tons of heavy brick usage, but also can save 80% of fire insulation materials.   4, Energy saving: Alumina bubble has obvious thermal insulation characteristics, low thermal conductivity, can play a very good thermal insulation effect, reduce heat emission, improve thermal efficiency, so as to save energy. The energy saving effect can reach more than 30%. Alumina bubble and its products is a kind of high temperature resistance, excellent energy saving light refractory material, in a variety of atmospheres are very stable. Especially in 1800℃ high temperature furnace application. Alumina bubble can be used for high temperature, super high temperature heat insulation filler, high temperature refractory concrete lightweight aggregate, high temperature castable, etc. Hollow ball brick can be used for high temperature energy saving (>30%) inverted flame kiln, shuttle kiln, molybdenum wire furnace, tungsten rod furnace, induction furnace, nitriding furnace, etc. For reducing the weight of the furnace body, reforming the structure, saving materials and energy, it will achieve obvious results.

Electrofused zirconium corundum brick also known as AZS electrofused zirconium corundum brick English abbreviation is AZS, is according to the three chemical composition of Al2O3-ZrO2-SiO2 terpolymer phase diagram, according to the content of the order, Al2O3 take A, ZrO2 take Z, SiO2 take S, the national standard uses this abbreviation, such as 33 fused cast zirconium corundum brick, Abbreviated as AZS-33#, No. 36 Fused cast corundum brick, abbreviated as AZS-36#, No. 41 fused cast corundum brick, abbreviated as AZS-41#.   Zirconium fused corundum brick is made of pure alumina powder with containing zirconium oxide 34% and silicon dioxide 65% zircon sand in electric furnace melting into a model cooling after internalization of white solid, the petrographic structure composed of zirconium corundum and inclined stone eutectoid and glass phase composition, tell from the reading is eutectoid zirconium corundum phase and slanting stone, glass phase between the crystallization of them.   The manufacturing process of electrosmelting cast brick combines selected zircon sand and industrial aluminum oxide powder according to 1:1, plus a small amount of Flux NaZO(added in the form of sodium carbonate) and B20 (added in the form of boric acid or borax), mixed evenly, melted at 1800~1900℃ and then cast into shape, can make the casting brick containing ZrO2 33%. On this basis, casting bricks containing ZrO2 of 36%~41% can be prepared by using partial desilicated zircon sand as raw material. Z irconia- eorundumrefraetory brick is a refractory product with 33%~45% ZrO2 content made from industrial alumina powder and selected zircon sand. Lead corundum brick is mainly used in glass industry kiln.   The AZS bricks produced by CH Purified tories have stable and compact microstructure and are highly resistant to glass liquid erosion. Welcome to contact us for detailed technical information and quotation of AZS bricks.

Refractories for Alining In the world non-ferrous metal production, the annual output of aluminum ranks first, far more than other non-ferrous metals. The aluminum industry consumes much more refractories each year than copper, lead and zinc smelters. The production method of metal aluminum is a fixed two-step method: the first step is to produce alumina from bauxite by wet method, and in the second step, aluminum is obtained by molten salt electrolysis with industrial alumina as raw material. The high temperature kiln used in the production process includes rotary kiln, molten salt electrolytic tank, molten aluminum furnace and so on. The refractory consumption of aluminum industrial furnace is very large. As a result, the alkali material in the Al2O3 material is especially serious to the refractory of rotary kiln. in the process of smelting aluminum, even at a lower temperature, metal aluminum still has a strong permeability. once it seeps into the brick, it will react with the SiO2 in the brick, reduce the Si, destroy the structure of the refractory, and make the lining produce metamorphic layer, loose, peeling and damaged. Response :3 SiO2 4Al---2Al2O3 3Si. Therefore, refractory materials containing SiO2 should not be used as furnace materials for metal aluminum smelting equipment. Therefore, the general aluminum industry furnace refractory, in addition to high aluminum brick, commonly used carbon products.

Refractories for zinc smelting There are two kinds of zinc smelting: pyrometallurgical smelting and hydrometallurgical smelting. The pyrometallurgical smelting mainly includes vertical pot zinc distillation furnace, tower distillation furnace, closed blast furnace and electrothermal zinc smelting, etc. Hydrometallurgical zinc smelting has the traditional two-end leaching method, that is, the leaching slag is treated by volatile kiln and hot acid leaching process, that is, the slag is treated by jarosite method, goethite method, hematite method, and the whole wet process pressure leaching process, zinc smelting with lead-zinc closed blast furnace, etc.   Distillation zinc smelting in China accounts for about 30% of the crude zinc smelting, and the refined zinc produced by tower zinc rectifying furnace accounts for 50% of the refined zinc products. Vertical zinc smelting process is one of the main processes of pyrometallurgical zinc smelting. Although there are few factories using this process abroad, a considerable amount of crude zinc is produced by this vertical zinc smelting process in China, and all the crude zinc produced by pyrometallurgical zinc is refined in the rectification furnace. The vertical pot zinc smelting distillation furnace is an equipment of fire zinc smelting heated by flame. It is composed of the tank body (tank body, upper extension, lower extension), combustion chamber, heat exchange chamber and condenser and other parts. The total height of large double pot furnace body can reach 20m. The principle is as follows: sintering agglomerates containing coke powder are added from the top of the furnace, the agglomerates run downward, and are briefly heated by the combustion chamber outside the tank. The ZnO in the agglomerates is reduced to gaseous Zn at 1200~1300℃, and the furnace gas containing Zn vapor enters the condensing tube from the upper extension of the furnace (600℃), condenses into liquid zinc, and the residual slag is discharged from the lower part.   The vertical tank is heated indirectly, and the tank is in reducing atmosphere. In addition, when the coke agglomerate moves in the tank, the inner wall of the tank body bears the friction of the agglomerate with high temperature and hardness, so the silicon carbide material with high thermal conductivity, high strength, strong corrosion resistance and high wear resistance is selected. At the same time, in order to ensure that the tank has a strong reducing atmosphere, the silicon carbide masonry must be carefully processed and constructed. In order to ensure good air tightness and thermal stability, sand sealing groove is generally used at the joint of cans (i.e. the two ends of the tank) and cans (i.e. the side walls of the tank). The condenser is also made of silicon carbide because of its good thermal conductivity. The combustion chamber is arranged on both sides of the tank, through heating the outer wall of the tank indirectly heating the ore in the tank, basically the same high as the tank, but the width is not large, is thin and high type, the temperature is 1300~1350℃, so the high temperature strength of refractory materials is high, currently with high quality high aluminum brick masonry. The temperature of the heat exchange chamber and condenser is not high, and clay brick masonry is generally used. Tower type zinc rectifying furnace is the most important equipment for refining zinc by fire process. It includes melting furnace, liquating furnace (including fractionation chamber), lead tower condenser, high cadmium zinc condenser, fine zinc storage tank and so on. In fact, it is the general name of multiple equipment, with complex structure. Lead tower and cadmium tower are the main equipment of the tower type zinc rectification furnace group. Their furnace type is similar, and in the middle is a group of dozens of trays stacked. Usually zinc rectification furnace is mainly composed of two lead tower and a cadmium tower. Distillation process is the use of zinc and other impurities boiling point is different and zinc boiling point is low (zinc 916℃, lead 1750℃, cadmium 765℃), the use of continuous fractionation principle will impurity metal (mainly lead, iron, cadmium, etc.) separation, in order to obtain fine zinc or 1~3 grade zinc. The distillation process is divided into two stages: the first stage is the separation of lead, iron, copper, tin, smoke and other high boiling point metals in the lead tower, and the production of lead (smoke), iron zinc alloy and cadmium free zinc in the furnace; The second stage is carried out in the cadmium tower. Cadmium-containing zinc produced in the condenser of the lead tower flows into the cadmium tower, and refined zinc is produced in the lower part of the tower after fractionation, while cadmium is enriched in the high cadmium zinc in the condenser. When method zinc, such as reduction, distillation and distillation process, because of the zinc vapor easy oxidation by oxygen, carbon dioxide and water vapor, so the zinc smelting reduction and distillation equipment generally adopt the method of closed or flame heating insulation for smelting, distillation airtight, not deformation, muffle layers should choose high thermal conductivity, high strength, and not with burden or zinc vapor reaction materials. In addition, the zinc vapor must be condensed and collected, generally equipped with condensing equipment, in order to splash the condensed zinc vapor into liquid zinc, the rotor used in the condenser rotates at a speed of 750~1000r/min, the material used in the rotor requires high thermal shock resistance and high temperature mechanical strength, and does not react with liquid zinc and zinc vapor. The tray in the tower zinc rectification furnace, because it is directly in contact with the metal vapor and melt, the material is required to have a good ability to resist the corrosion of metal vapor and melt, and has a high thermal conductivity and high strength, so the furnace lining with silicon carbide refractory is the best. Silicon carbide refractories with good chemical stability, high temperature strength, high thermal conductivity, good thermal shock resistance, abrasion resistance, resistance to erosion, was wet with metallic melts metal vapor erosion resistance, etc, the most suitable for zinc vertical distillation furnace wall, zinc distillation furnace tray, condenser and the rotor, in areas such as the key parts in the kiln with silicon carbide refractories, in addition, other parts also use sticky soil, high aluminum, magnesia and monolithic refractories.

Refractories for boilers Boiler as a thermal power equipment has a history of more than 200 years, it is an important equipment to convert the chemical energy stored in coal, oil or natural gas into water or steam heat energy. The heat energy of high temperature water and steam can be directly applied in life and production, such as air conditioning, textile, chemical, papermaking and other fields; it can also be converted into other forms of energy, such as electric energy, mechanical energy. With the expansion of thermal energy application of water and steam, boiler has gradually become an indispensable power machinery in all fields of production and life of human society. With the rapid development of material production and the increasing consumption of energy, human society needs more and more advanced energy conversion equipment, and the role and position of boiler industry in the national economy is becoming more and more important. Modern boilers can be seen as a huge steam generator. After coal, oil or natural gas are fed into the boiler, the combustion equipment burns it, and the chemical energy of the fuel is converted into the heat energy of the combustion product, the flue gas. High temperature flue gas transfers heat energy to feed water through various heat transfer modes, and water supplies heat energy in the form of steam or man to industrial and agricultural production and human life, or to generate electricity and act as the driving force for mechanical movement. The boiler for power generation is generally called power station boiler, while the boiler directly supplied to industrial and agricultural production or driving machinery is called industrial boiler or ordinary boiler. With the development of boiler industry, the capacity of industrial boiler or ordinary boiler has developed from producing hundreds of kilograms of steam per hour to producing dozens of tons of steam per hour, and the performance of boiler has also changed essentially. The efficiency of industrial boilers has been improved from 20%~30% to 70%~80%. The original heavy manual operation has now been mechanized and automated. Foreign industrial boilers mainly use oil and natural gas. Since the world energy crisis in the early 1970s, coal resources have been paid more attention to because of the high price of oil and gas fuel. However, in order to prevent environmental pollution, coal-fired boilers have developed greatly in purifying combustion products. The characteristics of foreign industrial boilers are large average single machine capacity, high thermal efficiency, perfect automation control degree, development of boiler units in the direction of fast loading or assembly, compact structure and convenient site installation. The industrial boilers in our country mainly use all kinds of raw coal, and the supply of coal varies greatly, so the actual operation thermal efficiency of the boiler is low. The single machine capacity is low, the automation control degree is low. In recent years, while absorbing the advanced technology of foreign countries, the boiler scientists in our country have made great progress in boiler design and have reached or approached the world level. The boiler manufacturing industry is also constantly updated, and the boiler manufacturing standards adopted in China have basically met the international standards. The ordinary boiler is composed of boiler pipe system, combustion chamber, flue and dust collector, and its working pressure is not high, which is mainly used in industrial and civil heating departments. This kind of boiler form is many, the quantity is big, most uses the coal as the fuel, also has burns the heavy oil or the gas. The working process of boiler is composed of combustion process and heat transfer process. Many and complex boiler components are designed to complete and strengthen these two processes. According to the working process of the boiler, the boiler can be divided into two parts: boiler body and combustion equipment.

Refractories commonly used in cement kilns 1. Alkaline refractories Alkaline refractories have excellent properties of high temperature calcination and chemical corrosion resistance, which are the key lining materials for cement kilns to achieve high quality, high yield, low consumption and long-term safe operation. However, it also has the main shortcomings of easy to be affected with damp metamorphism, high thermal expansion rate, high thermal conductivity and poor thermal shock resistance. At present, the imported and domestic basic refractories suitable for cement kilns mainly include direct bonded magnesia-chrome brick, semi-direct bonded magnesia-chrome brick, ordinary magnesia-chrome brick, dolomite brick, zirconium-containing and non-zirconium-containing special magnesia-chrome brick, spinel and chemically bonded non-burned magnesia-chrome brick. With the change of coal instead of oil in clinker calcination, the improvement of energy saving requirements, the improvement of corrosion resistance requirements of new dry cement kiln lining and the demand of reducing or even preventing chromium pollution and strengthening environmental protection, in recent years, the development and utilization of low chromium or even chromium free alkaline refractory for cement kiln has been presented. Low chromium and chromium free basic refractories. Ordinary magnesia chrome brick containing CR ₂O₃ often up to 8%~10%, directly combined with magnesia chrome brick 10%~16% larger. The favorable effect of adding chromium ore is to improve the thermal shock resistance of brick. However, they are used in cement kilns, especially in the new dry method cement kilns, which are vulnerable to alkali erosion, generating K₂CrO₄ containing 6 valent chromium and so on. The ₄ minerals are released to the environment. That is to say, the residue bricks can contaminate water equivalent to 50,000 to 250,000 times their own weight, seriously damaging the environment and threatening the health of the population. In order to improve the corrosion resistance of alkaline brick and reduce or even eliminate the chromium pollution to the environment, foreign countries have been devoted to the development and utilization of low cost magnesia-chrome brick, special magnesia-chrome brick and new type of dolomite brick and other alkaline refractory materials for many years, and have achieved success. China's chromium ore resources are poor, and remote western Xinjiang and Xizang, has been a large number of imports containing chromium alloy steel manufacturing, so the price soared. In cement kilns, it is more urgent to replace high chromium magnesia-chrome brick with low chromium and no-chromium basic brick and direct bonded magnesia-chrome brick. Low chrome magnesia chrome brick. Seawater magnesia is the main raw material for foreign direct - bonded magnesia - chrome brick. Brick chrome ore content is more, containing ω (CR ₂O+ FE ₂O₃) up to 16%~25%, chrome ore and magnesite direct combination, combining with containing compound spinel (Mg, Fe)O -(Mg, Fe)O· (Al, CR) ₂O₃ is a "rigid" combination. Its biggest advantage is the ability of high temperature, high flexural strength under 1500 ℃ hot and creep rate is small, thus make the thermal shock resistance of brick, alkali corrosion resistance and oxidation - reduction atmosphere change has quite a sacrifice, especially in open stop more frequently on the kiln and the use of alkali is higher in the original, fuel, had to shorten its service life. Has come out of a low chromium magnesia chrome brick is to coarse crystal high iron natural magnesia as raw material, coarse crystal magnesia interwoven in magnesite - magnesium ferrite - spinel matrix, (Mg, Fe) O-MgO· FE ₂O₃ combination still has better flexibility and plasticality at 1400℃. Brick with only a small amount of chrome ore particles, containing CR ₂O₃+ FE ₂O₃ only 10%~11%. Therefore, this kind of product in the thermal shock resistance, creep rate and alkali corrosion resistance between the more satisfactory balance, the brick lining due to heat and kiln body ellipticity caused by the internal stress lining ability is stronger, can not withstand very high temperature is its inherent characteristics. 2. High aluminum brick High alumina brick has higher compressive strength, softening temperature under load and better thermal shock resistance. Because of its low price and high quality, it is widely used in various cement kilns. Various types of phosphate-bonded high-alumina bricks are characterized by high strength (not less than 60MPa) and good thermal shock resistance, but they creep more under high temperature, so it is better to calcine high-alumina bricks when used in vault parts. In high aluminum brick, the introduction of a small amount of ZRO ₂, using the transformation between ZRO ₂ monoclinic and square type, can lead to the existence of microcracks and improvement of thermal shock resistance. The selection of appropriate grain size distribution makes the brick have higher apparent porosity, but also higher strength, and lower its thermal conductivity and thermal expansion. In the use of cement kiln, a thin layer of glaze film is formed on the brick surface to protect the brick from further alkali erosion. High-alumina brick suitable for cement kiln mainly includes phosphate bonded high-alumina brick, phosphate bonded high-alumina brick wear-resisting high-alumina brick, spalling high-alumina brick, chemically bonded (special) high-alumina brick, and ordinary high-alumina brick, etc. 3. Series alkali resistant brick Alkali-resistant brick has excellent alkali corrosion resistance, can react with alkali compounds in kiln material and kiln gas at a certain temperature and quickly form a closed and dense protective glaze layer on the brick surface, which can prevent the continuous infiltration of alkali and the damage of brick "alkali crack". It is one of the indispensable kiln lining materials for cement rotary kiln, especially for new type dry kiln. The alkali - resistant brick series include ordinary alkali - resistant brick, high strength alkali - resistant brick, alkali - resistant insulation brick and arch - resistant brick. 4. Series refractory castables Refractory castable has been widely used in cement kiln system, especially in preheater system with complex structure, because of its simple production process, low energy consumption and flexibility in use. The refractory castables suitable for cement kilns mainly include rigid jade castables, high aluminum castables, alkali resistant castables and light castables. 5. Performance of heat insulation material The commonly used insulation materials for cement kiln systems are insulating bricks, insulating plates and insulating (lightweight) castables. In order to ensure the convenience, good quality and good use effect of brick lining, in addition to the internal quality and uniformity of refractory materials, the quality of brick appearance must be strictly controlled. This is especially important for large kilns.

Refractories for glass kilns Glass kiln has many forms, such as flat tank kiln, horizontal flame flow tank kiln and horseshoe flame flow tank kiln, among which flat glass kiln is divided into three parts: tank kiln, regenerative chamber and tin tank. In addition, there are L hanging wall, electric flux, bubbling and melt division device, tin tank. The bottom of the pool is made of large clay bricks, which are laid with zirconium or AZS ramming material. The melting part is then paved with 33 AZS bricks by electrofusion without shrinkage hole oxidation method. When the requirements are not high, the bottom of the pool before the hot spot can also be paved with sintered AZS bricks. Cooling section with α-β-Al₂O₃ casting brick pavement, when the requirements are not high available No. 33 shrinkage shrinkage oxidation method electric melting AZS brick. The wall of the melting pool shall be constructed by the whole No. 33, No. 36 and No. 41 oxidation electrofused AZS bricks. The bricks produced by dense casting or inclined casting can be selected according to the erosion condition, but the No. 41 AZS bricks without shrinkage cavity shall be selected for the corner bricks. The liquid line of the wall brick should be air-cooled or water-cooled, and the other parts can be insulated by non-asbestos calcium silicate board. Cooling part of the pool wall using α-β-Al₂O₃ casting brick, low requirements can also use No. 33 oxidation method inclined casting AZS brick. The parapet of the melting zone is made of 33 AZS electric fused brick without shrinkage hole. Clarification area and cooling parapet using high quality silicon brick, high requirements can be used β-Al₂O₃ casting brick. L The nose of the hanging wall is made of 33 electric fused AZS sintered zirconium mullite composite brick. The AZS portion of the brick has a T-hook; Part of zirconium mullite has sigma ─ ─ groove. The two are connected by mechanical occlusion. When the requirements are not high, zirconium mullite bricks with good sintering, normal porosity, good volume stability at high temperature and main crystalline phase of mullite and plagioclase zircon can be used. High quality zirconium mullite bricks are used above the composite bricks. The top layer is made of high-quality silicon bricks. The rear gable of the glass kiln and the traditional front face wall can be made of high quality silicon brick. L Both domestic and imported zirconium mullite sintered bricks used in the hanging wall have repeatedly spalled off. After spalling occurs, a large number of stones appear in glass products, and the qualified rate of products and the economic benefit of the factory are seriously affected. The main reason is the use of sintered not good enough, high porosity or contain a lot of zirconite brick. Zirconite is an acidic mineral, which will decompose quickly in the presence of high temperature and high concentration of alkali vapor, forming low melt and promoting the mullite Xia petrification reaction. In the presence of zirconite, the volumetric effect of fossilization is +39%. The volume change produces large stresses, which cannot be relaxed, resulting in spalling. Melted crown using high quality silica brick. High quality silicon brick for SIO ₂ content 96%, melting index (Al₂O₃+2*R₂O) less than 0.5%, true density is not more than 2.34 or 2.35, and has a small size tolerance. Silica brick is sealed with amorphous material first, relay insulation layer. The main mechanism of arch walling damage is through upward droughtings or "rat holes". The "rat hole" is the alkali vapor that escapes from the kiln condenses in the brick seam and corrodes the silicon brick. The erosion products with low viscosity run off along the brick seam, causing the further expansion of the gap. The key to prevent "rat hole" is to design the temperature field in the refractory in advance, so that the alkali vapor can condense on the amorphous refractory rather than in the cracks of the silicon brick. The top of the regenerator by NA ₂O, flying material and high temperature compound effect. The erosion of the middle and lower parts of the regenerator is mainly rich in mirabilite. 98%~97% and 96%~95% magnesia bricks are used for the lattice without special requirements at 1300~1100℃. Directly bonded magnesia-chrome brick was used at 1100~800℃. Low porosity clay bricks were used below 800℃. Magnesium chromium refractories in CR ₂O₃ to improve the resistance of materials to mirabilite erosion has a good effect. However, in order to avoid chromium pollution, magnesia zirconium brick (magnesia aggregate + magnesia olivine + plagic zircon matrix) or pure spinel brick can be used instead of magnesia chrome brick. Tin trough bottom brick is generally composed of large refractory brick, sealing and filling material, graphite products and stainless steel fixed parts. The bottom brick is fixed on the bottom plate by screw; The upper part of the bolt is covered by an inverted tapered amorphous refractory solidified material. In case of tin solution along the edge of the inverted taper hole invasion, it can not make the solidified amorphous material surface, fall off. The main function of graphite powder and graphite gasket is to protect the bolt from the erosion of the leaking tin liquid, so that the bolt can reliably and permanently play a fixed role and prevent the bottom brick from floating. In addition to the properties of conventional refractories, tin trough bottom brick also requires low fossilization tendency, hydrogen diffusion, high strain rate and surface accuracy. Reduce the trend of Xia petrification method: one is to control the content of Al₂O₃ is 38%~43%, significant porosity is not more than 23%; The second is to control the content of AL ₂O₃ is 43%~48%, and the apparent porosity is not greater than 15%. Hydrogen diffusion is used to characterize the gas permeability index, its value should not be greater than 1.5KPa (150mmH₂O). Strain rate is the maximum percentage of deformation of a material before compression failure. The strain rate is high, the deformation of the material is large after compression, and the brick seam can be left narrow, which can also reduce the possibility of tin leakage and bottom brick being pulled out by buoyancy. There is a correlation between porosity and strain rate. The porosity and strain rate are high, but the corrosion resistance is poor and the petrifaction tendency increases accordingly. Domestic and foreign products have their own advantages. Foreign bricks are characterized by low aluminum, high porosity, high diffusivity and high strain rate. Domestic bricks are characterized by blast furnace, low porosity, low diffusivity and low strain rate. The combined modular structure of siliconite brick and insulation brick is used to construct the tin groove roof in foreign countries. In the early stage of our country, prefabricated blocks of heat-resistant reinforced concrete were used to construct the tin groove roof, and then the combined tin groove roof was developed. The supporting module adopts prefabricated parts; The heating module is made of mullite fired brick and the electric heating element is installed on the module. This structure combines the advantages of prefabricated parts and sintered bricks: low cost, easy installation, good flexibility of electric heater arrangement, and long service life. The prefabricated parts used for tin tank top had better be treated at high temperature to completely remove the bound water and obtain stable structure and performance.