Alumina
The alumina , or Oxide of Aluminum , is a chemical compound which exists in a natural state in the Bauxite, in the form of hydrated alumina mixed with Oxide iron.
Alumina was isolated in 1754 by the German chemist Marggraf starting from alum. It is Louis Guyton de Morveau (1737-1816), collaborator of Lavoisier, which baptized alumina one of sulfates contained in the Alun.
The Extraction of alumina of bauxite is carried out according to a chemical process called proceeded Bayer invented by the Austrian Karl Josef Bayer.
Alumina is exploited industrially to obtain Aluminum by the proceeded electrolytic Héroult-Hall. It is also used as refractory material (resistant to the very strong temperatures) and like Céramique, and can be also used in the form of Corindon to manufacture abrasives.
Several invaluable stones is containing alumina anhydrous, coloured or not by lic Oxyde S Métal: Ruby, topaz, Sapphire.
Properties of alumina
Polymorphic of alumina
Statistics of production
Source
International Aluminum Institute (http://www.world-aluminium.org/iai/stats/index.asp)
The values include the alumina intended for the production of aluminum (the most important proportion) as well as the alumina intended for other uses.
Notes and references of the article
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