 |
|
|
|
|
|
|
Refining bauxite into alumina
Bauxite ore is not used directly to make aluminum. It must first be refined into aluminum oxide, or alumina. Alcoa is the world's leading producer of alumina, with global refinery capacity of 14 million metric tons per year, nearly a third of the international market. We operate refineries in Australia, Brazil, Jamaica, Spain, Suriname and the United States. Our three-refinery operation in Western Australia is the world's biggest single source of alumina, able to supply 15% of the international market.
Alumina is a white granular material, a little finer than table salt, and is properly called aluminum oxide. The Bayer refining process used by alumina refineries worldwide involves four steps - digestion, clarification, precipitation and calcination. To turn bauxite into alumina, we grind the ore and mix it with lime and caustic soda, pump this mix into high-pressure containers, and heat it. The aluminum oxide is dissolved by the caustic soda, then precipitated out of this solution, washed, and heated to drive off water. What’s left is the white powder called alumina, which is transformed into aluminum metal in the smelting process.
Alcoa refining sets world standards
In 1992, the Kwinana refinery in Western Australia, owned by Alcoa World Alumina and Chemicals (a 60/40 partnership between Alcoa and WMC), became the first alumina refinery in the world to achieve an ISO 9002 Quality Accreditation. Our other two Australian refineries, Pinjarra and Wagerup, achieved this standard in 1994, along with Alcoa's Western Australia bauxite mining operations. Similarly Kwinana refinery led the way in 1997 in achieving ISO 14001 environmental management certification. Alumar, a combined refinery and smelter in São Luís, Brazil, achieved both certifications in 2000. The largest such operation in South America, Alumar is owned in part by Alcoa Aluminio S.A., an integrated aluminum producer of which Alcoa owns 59.1%.
Standalone Bauxite Mine Interests
|
|
|
|
|
|
