bauxite


bauxite
bauxitic /bawk sit"ik, boh zit"-/, adj.
/bawk"suyt, boh"zuyt/, n.
a rock consisting of aluminum oxides and hydroxides with various impurities: the principal ore of aluminum.
[1860-65; named after Les Baux, near Arles in S France; see -ITE1]

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Most important aluminum ore, of varying compositions in which aluminum hydroxide or aluminum oxide predominate (named for Les Baux in southern France, where the ore was identified in 1821).

The other constituents are largely iron oxide, silica, and titania. Bauxite has been found in all the continents except Antarctica. Known deposits can supply the world with aluminum for hundreds of years at present production levels.

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ore
      rock largely composed of a mixture of hydrous aluminum oxides. Bauxite is the principal ore of aluminum.

      Bauxites vary physically according to the origin and geologic history of their deposits: some deposits are soft, easily crushed, and structureless; some are hard, dense, and pisolitic, or pealike; still others are porous but strong or are stratified or largely pseudomorphic after parent rock. The laterite type is commonly pisolitic and mottled, with pisolites ranging in size from about 2.5 mm (0.10 inch) to 25 cm (10 inches) or more in diameter. Both pisolites and groundmass (matrix) may exhibit great colour variations; common colours are pink, cream, red, brown, yellow, and gray. Exposed surfaces of lateritic ore are rough, often lavalike, with a wormlike structure and variegated colours on vertical faces. Such material tends to harden or reconsolidate on exposure to air. Although terra-rossa types are granular and earthy, they also may possess pisolitic structures.

      Bauxite is formed by the thorough weathering of many different rocks. Clay minerals commonly represent intermediate stages, but some bauxites appear to be reworked chemical precipitates rather than simple alteration products. Bauxite may grade into laterite or clay, laterally or vertically.

      Constituent minerals are rarely recognizable in hand specimens, and even in thin sections complete identification may be difficult. Combined petrography, X-ray diffraction, and differential thermal analysis have shown that gibbsite, boehmite, and diaspore, alone or in mixtures, are the constituent minerals. Clay minerals, hematite, magnetite, goethite, siderite, and quartz are common impurities. Most deposits contain rutile, anatase, zircon, and other minerals.

      Bauxite is found in most countries, but the larger deposits occur in the tropics. Monohydrate ores have been extensively mined, for example, in France, Italy, and Greece; and trihydrate ores in Arkansas, U.S., and in Suriname, Guyana, and Jamaica. Gibbsite-rich ores occur in Ghana, Guinea, India, and Brazil. Major deposits of gravels mixed with sand were discovered in Australia in the 1950s. Deposits in the Ural Mountains and in northern Asia are largely diaspore.

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Universalium. 2010.

Look at other dictionaries:

  • Bauxite — ou minerai d aluminium Bauxite (Hérault) avec des pisolites …   Wikipédia en Français

  • Bauxite — is the most important aluminium ore. It consists largely of the minerals gibbsite Al(OH)3, boehmite γ AlO(OH), and diaspore α AlO(OH), together with the iron oxides goethite and hematite, the clay mineral kaolinite and small amounts of anatase… …   Wikipedia

  • bauxite — [ boksit ] n. f. • 1847; des Baux de Provence ♦ Roche siliceuse alumineuse formée surtout d alumine, plus ou moins riche en oxydes de fer (bauxite rouge), en titane et en vanadium. La bauxite, principal minerai d aluminium. ● bauxite nom féminin… …   Encyclopédie Universelle

  • Bauxite — Bauxite, AR U.S. town in Arkansas Population (2000): 432 Housing Units (2000): 171 Land area (2000): 2.392685 sq. miles (6.197025 sq. km) Water area (2000): 0.056432 sq. miles (0.146158 sq. km) Total area (2000): 2.449117 sq. miles (6.343183 sq.… …   StarDict's U.S. Gazetteer Places

  • Bauxite, AR — U.S. town in Arkansas Population (2000): 432 Housing Units (2000): 171 Land area (2000): 2.392685 sq. miles (6.197025 sq. km) Water area (2000): 0.056432 sq. miles (0.146158 sq. km) Total area (2000): 2.449117 sq. miles (6.343183 sq. km) FIPS… …   StarDict's U.S. Gazetteer Places

  • bauxite — 1861, clayey mineral containing aluminum, from Fr. bauxite (1821), from Les Baux, near Soles, where it was first found. The place name is from Prov. Li Baus, lit. the precipices …   Etymology dictionary

  • Bauxite — Baux ite, Beauxite Beaux ite,n. [F., fr. Baux or Beaux, near Arles.] (Min.) A ferruginous hydrate of alumina. It is the most commonly used ore for the preparation of aluminum and alumina. It is also used for the lining of furnaces which are… …   The Collaborative International Dictionary of English

  • Bauxite — Bauxite. См. Боксит. (Источник: «Металлы и сплавы. Справочник.» Под редакцией Ю.П. Солнцева; НПО Профессионал , НПО Мир и семья ; Санкт Петербург, 2003 г.) …   Словарь металлургических терминов

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  • bauxite — ► NOUN ▪ a clayey rock that is the chief ore of aluminium. ORIGIN from Les Baux, a village in SE France, where it was first found …   English terms dictionary

  • bauxite — [bôks′īt΄, bō′zīt΄] n. [Fr, after (Les) Baux, town near Arles, France] a soft, claylike sedimentary rock, mainly hydrous aluminum hydroxide, that is the chief ore of aluminum …   English World dictionary


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