The
Bayer process is the principal industrial means of refining
bauxite to produce
alumina (aluminium oxide). Bauxite, the most important ore of
aluminium, contains only 30–54%
aluminium oxide, (alumina), Al
2O
3, the rest being a mixture of
silica, various
iron oxides, and
titanium dioxide. The aluminium oxide must be purified before it can be refined to aluminium metal.