Alumina is an inorganic compound with high hardness, high melting point, high corrosion resistance and high insulation. The chemical formula is Al₂O₃, which is the main oxide of aluminum. There are mainly has α-Al₂O₃, γ-Al₂O₃, δ-Al₂O₃ and other categories, among which α-Al₂O₃ is the most stable and common crystalline phase of alumina. Aluminum oxide is widely used in industry and is an important industrial raw material with a wide range of applications.

Alumina is mainly used in the following areas:

1. Precision polishing: The high temperature calcined α-Al2O3 powder has the advantages of high hardness and strong grinding power. It is widely used in consumer goods processing industry, aerospace industry, automotive industry, casting/die casting, optics, semiconductor industry, etc., and surface treatment fields to achieve high surface finish.

2. Fine ceramics: With high hardness, high melting point and high insulation, aluminum oxide is an important raw material for the preparation of fine ceramics, which is widely used in ceramic products, abrasive materials, electronic components and other fields.

3. Aluminum: Aluminum oxide is one of the important raw materials for aluminum production, and can be reduced to aluminum metal by electrolysis and chemical methods.

4. Fireproof materials: The high melting point and incombustibility of alumina make it an important fireproof material, and it is widely used in the fields of construction and transportation.

5. Other uses: Alumina is also used in the preparation of high temperature corrosion resistant materials, coatings, electrolyte materials, insulation materials and other aspects.