Aluminium is refined from bauxite ore, with major reserves found in Guinea, Australia, Brazil, Jamaica and India. Aluminium is primarily used for building and construction as it is light, strong, able to conduct electricity and is resistant to corrosion. In order to produce alumina, sodium hydroxide is used to dissolve the bauxite ore at a high temperature. Sodium aluminium floride is then added to this liquid to smelt the alumina into aluminium. This refining process creates a toxic sledge known as “red mud,” which contains iron oxide, titanium oxide, sodium alumina-silicate and trace amounts of zinc, phosphorous, nickel and vanadium. Aluminium smelters are energy intensive, consuming between 14- 21 kWh to produce one kilogram of aluminium from alumina. Emissions from aluminium smelters contribute to the generation of acid rain and greenhouse gases.
[Adapted from the Mineral Policy Institute Backgrounder #1: Aluminium. Further information provided by the International Aluminium Institute.]
For a diagram of the process to produce aluminium from bauxite, please click here.
21 October 2006, 3:22pm EDT