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Why can't use high aluminum brick as the lining in the alkali corrosive atmosphere

May 30, 2022

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.