Aluminium is the most abundant metal in the earth's crust. It comes from bauxite which is refined into alumina - a fine white granular powder. This is the basis for aluminium production.
http://www.alcoa.com/global/en/about_alcoa/pdf/startswithdirt.pdf
http://www.alcoa.com/alumina/en/info_page/alumina_defined.asp
http://www.alcoa.com/global/en/about_alcoa/pdf/startswithdirt.pdf
http://www.alcoa.com/ingot/en/info_page/making_overview.asp
Alumina Limited has a 40% interest in Alcoa World Alumina and Chemicals (AWAC) which has a worldwide network of refineries providing 25% of global alumina production capacity.