Black corundum is primarily composed of aluminum oxide (Al2O3) with a content of 70% to 80%, containing a significant amount of impurities such as silicon oxide and titanium oxide, and is a black-colored variety of corundum. It is a new type of environmentally friendly material. Many users may not be aware of its specific applications, so we will provide a detailed introduction to its content next.

The application disciplines include Mechanical Engineering (Level 1 and related disciplines); Abrasive Materials (Level 2 discipline); and Abrasive Materials (Level 3 discipline). Black Corundum, also known as Low-Alumina Corundum, is a gray-black crystalline substance primarily composed of α-Al2O3 and magnetite, obtained by melting bauxite in an electric arc furnace. It is characterized by a lower Al2O3 content and the presence of a certain amount of Fe2O3 (about 10%), which gives it moderate hardness, high toughness, high-temperature resistance, and stable thermal properties. It is widely used in free grinding, such as pre-plating finishing and coarse grinding of products, mainly for stainless steel, metal products, optical glass, and bamboo and wood products for polishing and sandblasting. It is also a novel abrasive material for manufacturing resin sand wheels, cutting blades, and sandpapers.

The smelting process is essentially the same as that for brown fused alumina production. The method involves selecting high-quality bauxite, iron oxide, and other raw materials, adding trace elements, and then carefully smelting them in a tilting electric arc furnace. This ensures that the resulting black sintered alumina blocks are of top grade, with minimal impurities, high purity, and stable quality. It lays the foundation for producing sand segments with moderate hardness, good toughness, and excellent performance, as well as granular and micro-fine sands.