酸化アルミニウム
Aluminium oxide is an amphoteric oxide of aluminium with the chemical formula 23. It is also commonly referred to as alumina or aloxite in the mining, ceramic and materials science communities. It is produced by the Bayer process from bauxite. Its most significant use is in the production of aluminium metal, although it is also used as an abrasive due to its hardness and as a refractory material due to its high melting point.