Corundum refractories can also be called alumina refractories, which are the most mature, earliest developed and most widely used refractories among high melting point oxides.There are many types of corundum-based refractory materials. The traditional corundum-based refractory materials include white corundum, tabular corundum, sub-white corundum, dense corundum, brown corundum and chrome corundum.Among them, white corundum is a product obtained by melting and cooling industrial alumina or calcined alumina as the raw material. Due to the characteristics of the raw material itself, the porosity of white corundum is relatively high and contains more closed pores;Dense corundum is made of industrial alumina as raw material, and is smelted in an electric arc furnace by adding some additives. It is characterized by high density;Brown corundum is made by lightly burning high alumina bauxite as raw material, adding a small amount of carbon and iron filings and smelting in an electric arc furnace;Subwhite corundum is generally also called alumina-based fused corundum. It is made by smelting first-grade or super-grade bauxite at high temperature by adding reducing agent. The above four types of corundum are all made by fusing method.In addition, there is a sintering method to prepare corundum raw materials, such as tabular corundum. Sintered corundum is low-porosity alumina produced by high-temperature calcination with industrial alumina as raw material.