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.