What Is the Chemical Composition of Bauxite?

chemical-composition-bauxite Credit: Oliver Strewe/Lonely Planet Images/Getty Images

Bauxite is an aluminum ore that consists primarily of aluminum oxide and aluminum hydroxide minerals, mixed with two iron oxides, the clay mineral kaolinite and small amounts of anatase. The aluminum oxide mineral is gibbsite, or Al(OH)3. The aluminum hydroxide minerals are boehmite and diaspore, or γ-AlO(OH) and α-AlO(OH), respectively.

The two iron oxides found in bauxite are the iron-bearing hydroxide goethite, or α-FeO(OH), and hematite, or Fe2O3. Kaolinite is a layered silicate mineral with the molecular formula Al2Si2O5(OH)4. Anatase, or TiO2, is a mineral form of titanium dioxide. Bauxite is the world's main source of aluminum. According to Geology.com, the top three bauxite-producing countries in 2010 were Australia, China and Brazil.