Chem

The Bayer process

aluminium-bearing ore called Bauxite is extracted from the mines.

Bauxite (Hydrated aluminium oxide Al2O3.3H2 or aluminium oxide trihydrate or alumina trihydrate) is crushed, washed and dried.

Caustic soda ( sodium hydroxide, NaOH) dissolves the bauxite at high temperature of 140 degrees celsius to form a solution of sodium aluminate. The chemical formula for the following process.

Al2O3H2O (s) + 2NaAlO29(aq) —- 2NaAlO2(aq)+ 4 H2O(l).

Remaining impurities such as hydrated aluminium oxide, iron oxide, silica, and titania must be filtered out removed during the refining process, otherwise they will contaminate the metal during the smelting process.