bauxite(redirected from Alcrete)
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bauxite(bôk`sīt, bŏk`–), mixture of hydrated aluminum oxides usually containing oxides of iron and silicon in varying quantities. A noncrystalline substance formerly thought to be a mineral, bauxite is claylike and earthy and ranges in color from white to deep brown or red according to the nature and quantity of its components. Bauxite occurs characteristically in pisolitic form, i.e., composed of small, round concretions. Its composition varies, alumina constituting from about 50% to about 70%. First discovered in Les Baux, France, bauxite is widely distributed, with important deposits occurring in Africa, South America, Russia, the West Indies, and the United States (Alabama, Arkansas, and Georgia). It is the chief source of aluminum and of its compounds, including alumina, alums, and alundum. It is used in the preparation of abrasives and as a refractory for spark plugs and furnace linings.
A whitish, grayish, brown, yellow, or reddish-brown rock composed of hydrous aluminum oxides and aluminum hydroxides and containing impurities such as free silica, silt, iron hydroxides, and clay minerals; the principal commercial source of aluminum.
a white, red, yellow, or brown amorphous claylike substance comprising aluminium oxides and hydroxides, often with such impurities as iron oxides. It is the chief ore of aluminium. General formula: Al2O3.nH2O