Alumina from Bauxite. Extraction and Production of Alumina from Bauxite
Alumina is the common name given to aluminum oxide (Al2O3). Alumina is produced from bauxite, an ore that is mined from topsoil in various tropical and subtropical regions. The Bayer process, discovered in 1887, is the primary process by which alumina is extracted from bauxite.
Bauxite is the general name given to the hydrated oxides of aluminium. It contains varying amounts of combined water and several impurities of which ferric oxide and silica are usually predominant. It is essential that the Al2O3 (alumina) be obtained substantially free from these impurities as otherwise the iron oxide and silica would be reduced and contaminate the metallic aluminium produced in the Hall (or Heroult) Process.