High alumina bricks are differentiated based on the amount of aluminum oxide (Al2O3) content. Currently, 48%, 55%, 60%, 65%, 73%, 75% content are often used, and of course there are higher content. The above is attributed to corundum.

According to the content of 55 or less, it is called clay brick, which is a neutral refractory material, which is made of bauxite or other materials with higher alumina content. It has high thermal stability, and the refractory temperature is around 1700°C. It is used for the lining of glass melting furnaces, cement rotary kilns, and steel-making electric furnaces. Of course, there are some high-alumina clay bricks and finished high-alumina bricks with high softness, low creep, and low porosity. According to different application needs, the ratio of raw materials is only important in production.

High alumina bricks and clay bricks are not only different in alumina content. Their production processes are similar, but the clinker blending is higher in the blending, which can reach 90-95%, and the firing temperature is also higher than that of clay bricks. It is much higher. In the actual test, the first and second high alumina bricks are mostly used in tunnel kilns with temperatures between 1500-1600°C, blast furnaces, furnace roofs, reverberatory furnaces, rotary kiln linings, and many other kilns.