Bauxite is the primary source of aluminium metal, and about 85% of bauxite mined is processed via the Bayer Process to make alumina trihydrate (ATH), then smelter grade alumina (SGA) from which aluminium metal is derived.
The respective processes take place in an alumina refinery and aluminium smelter, which may or may not be integrated.
The remaining 15% of crude bauxite mined is used to produce a range of non-metallurgical bauxite grades and non-metallurgical alumina grades.
There are three main bauxites types – boehmite, diaspore, and gibbsite – which each differ in chemical and physical characteristics, and each have predominance in certain regions of the world.
Owing to their different characteristics, bauxites are carefully selected for non-metallurgical uses as demanded by the required end use specifications of the derived bauxite and alumina grades.
According to the USGS, 201m. tonnes of bauxite was mined in 2009.
Although metallurgical grade bauxite may be suitable for certain non-metallurgical applications, such as in cements and slag conditioning, most non-metallurgical bauxites are confined to specific regions in Australia, Brazil, China, France, Guinea, Greece, Guyana, Turkey and the USA.
The primary sources of non-metallurgical bauxite are China, Greece, Guyana and Turkey.
About 5% of bauxite is mined and processed for direct use as non-metallurgical bauxite grades. Raw, uncalcined bauxite is used for cement, slag conditioning, and chemicals.
Calcined bauxite is produced to make abrasive, refractory, welding, and proppant grades.
Abrasive grade bauxite is fused to manufacture brown fused alumina used in abrasives and refractories.