Black fused alumina, also known as low-aluminum corundum, is a gray-black crystal with α-Al2O3 and iron spinel as the main ore phase, which is obtained by melting aluminum bauxite in an electric arc furnace. It is characterized by low Al2O3 content. There is a certain amount of Fe2O3 (about 10%), so it has the characteristics of moderate hardness, high toughness, high temperature resistance and stable thermal performance. It is mostly used for free grinding, such as grinding and rough grinding before electroplating of products. It is mainly used for polishing and sand blasting of stainless steel, metal products, optical glass, bamboo and wood products, and is also a novel abrasive for manufacturing resin grinding wheels, cutting sheets and abrasive cloths.