Aluminum oxide is made from bauxite through chemical treatment by removing the oxide of silicon, iron, titanic, etc. It is a raw material for aluminum oxide in high purity. It is a white solid that hardly soluble in water and with high hardness. Besides, aluminum oxide is odorless and flavorless; it is also hygroscopic but is note deliquescent. Furthermore, the burnt aluminum oxide is non-hygroscopic. It is a kind of amphoteric oxide, soluble in inorganic acid and basic solution. It is hardly soluble in water and non-polar organic solvents; the relative density is (d204)4.0; the melting point is 2050℃.