Extraction of Metals

Reduction of Oxides by Electrolysis

Reduction of Oxides by Electrolysis

It is possible to extract metals which make ionic oxides through electrolysis of the metal oxides. However, because this is an expensive process it is usually used only for metals which are too reactive to be reduced by chemical methods. For example, aluminium.

The third most abundant element within the Earth’s crust and the most abundant metal in the world, aluminium is found mainly as bauxite, an impure form of aluminium oxide (Al2O3).

Aluminium is very important within the commercial sector, within nearly 800 million tonnes being extracted every year from bauxite.

Aluminium extraction takes place in two main steps:

  • purification of Al2O3 from bauxite
  • electrolysis of the purified Al2O3


Extraction of aluminium

After the bauxite has been purified it is possible to begin electrolysis.

The melting point of Al2O3 is 2000