Bauxite is the most important aluminium ore. The United States one-cent coin is a unit of Currency equaling one one-hundredth of a United States dollar. WikipediaNaming An ore is a volume of rock containing components or Minerals in a mode of occurrence that renders it valuable for mining 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 TiO2. Gibbsite, Al(OH3 is one of the mineral forms of Aluminium hydroxide. Boehmite or Böhmite is an Aluminium oxide hydroxide (γ-AlO(OH mineral a component of the aluminium ore Bauxite. For the plant structure see Spore#Diaspore. For the similar word see Diaspora Diaspore is a native Aluminium oxide hydroxide Goethite, named after the German Polymath Johann Wolfgang von Goethe, is an iron bearing oxide mineral found in soil and other low temperature environments Hematite, also spelt hæmatite, is the Mineral form of Iron(III oxide (Fe2O3 one of several Iron oxides Kaolinite is a Clay mineral with the chemical composition Al 2 Si 2 O 5( OH)4 Anatase is one of the three Mineral forms of Titanium dioxide, the other two being Brookite and Rutile. It was named after the village Les Baux-de-Provence in southern France, where it was first discovered in 1821 by geologist Pierre Berthier. Les Baux-de-Provence is a commune in the Bouches-du-Rhône department in southern France, in the province of Provence Pierre Berthier ( July 3, 1782 &ndash August 24, 1861) was a French Geologist and mining engineer.
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Bauxite formation
Lateritic bauxites (silicate bauxites) are distinguished from karst bauxites (carbonate bauxites). Karst topography is a landscape shaped by the dissolution of a layer or layers of soluble Bedrock, usually Carbonate rock such as Limestone The early discovered carbonate bauxites occur predominantly in Europe and Jamaica above carbonate rocks (limestone and dolomite), where they were formed by lateritic weathering and residual accumulation of intercalated clays or of clayey dissolution residues of the limestone. Limestone is a Sedimentary rock composed largely of the Mineral Calcite ( Calcium carbonate: CaCO3 Dolomite (ˈdɒləmaɪt is the name of a Sedimentary Carbonate rock and a Mineral, both composed Weathering is the decomposition of earth rocks, Soils and their Minerals through direct contact with the planet's Atmosphere.
The lateritic bauxites occur in many countries of the tropical belt. They were formed by lateritization (see laterite) of various silicate rocks such as granite, gneiss, basalt, syenite and shale. Laterite (from the Latin word "later" meaning brick or tile is a surface formation in hot and wet tropical areas which is enriched in Iron and Aluminium Granite (ˈɡrænɪt is a common and widely occurring type of intrusive, Felsic, igneous rock. Gneiss (ˈnaɪs is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from preexisting formations that were originally Basalt (bəˈsɔːlt ˈbeisɔːlt ˈbæsɔːlt is a common Extrusive Volcanic rock. Syenite is a coarse-grained intrusive Igneous rock of the same general composition as Granite but with the Quartz either absent or present in relatively Shale (also called mudstone) is a fine-grained Sedimentary rock whose original constituents were Clay minerals or Muds It is characterized by Compared with iron-rich laterites, the formation of bauxites demands even more intense weathering conditions with a very good drainage. This enables dissolution of kaolinite and precipitation of gibbsite. Zones with highest aluminium content are frequently located below a ferruginous surface layer. Altogether there are sixteen known Iron Oxides and oxyhydroxides The aluminium hydroxide in the lateritic bauxite deposits is almost exclusively gibbsite.
Production trends
In 2007, Australia was the top producer of bauxite with almost one-third world share, followed by China, Brazil, Guinea and Jamaica. Although aluminum demand is rapidly increasing, known reserves are sufficient to meet the needs for a considerable time. Increased aluminum recycling, which has the advantage of lowering the energy costs of production, will help extend Bauxite reserves.
| Country | Mine production | Reserves | Reserve base | |
|---|---|---|---|---|
| 2006 | 2007 | |||
| Australia | 62,300 | 64,000 | 5,800,000 | 7,900,000 |
| People's Republic of China | 21,000 | 32,000 | 700,000 | 2,300,000 |
| Brazil | 21,000 | 24,000 | 1,900,000 | 2,500,000 |
| Guinea | 14,500 | 14,000 | 7,400,000 | 8,600,000 |
| Jamaica | 14,900 | 14,000 | 2,000,000 | 2,500,000 |
| India | 12,700 | 13,000 | 770,000 | 1,400,000 |
| Russia | 6,600 | 6,000 | 200,000 | 250,000 |
| Venezuela | 5,500 | 5,500 | 320,000 | 350,000 |
| Suriname | 4,920 | 5,000 | 580,000 | 600,000 |
| Kazakhstan | 4,800 | 4,900 | 360,000 | 450,000 |
| Greece | 2,450 | 2,400 | 600,000 | 650,000 |
| Other countries | 5,460 | 6,800 | 3,400,000 | 4,000,000 |
| World total (rounded) | 178,000 | 190,000 | 25,000,000 | 32,000,000 |
Source: U. This article is about the tonne or metric ton For other tons see Ton. For a topic outline on this subject see List of basic Australia topics. Talk People's Republic of China) PEOPLE'S REPUBLIC OF CHINA ARTICLE GUIDELINES |utc_offset = -2 to -4 |time_zone_DST = BRST |utc_offset_DST = -2 to -5 |cctld Guinea, officially Republic of Guinea (pronounced /ˈgɪni/ République de Guinée is a country in West Africa, formerly known as French Guinea Jamaica (ˈdʒəˈmeɪkə} is an Island nation of the Greater Antilles, in length and as much as in width situated in the Caribbean Sea. India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country Russia (Россия Rossiya) or the Russian Federation ( Rossiyskaya Federatsiya) is a transcontinental Country extending Venezuela (ˌvɛnəˈzweɪlə) officially the Bolivarian Republic of Venezuela (Spanish República Bolivariana de Venezuela) is a country on the Suriname ( Dutch: Suriname; Sranan Tongo: Sranan) officially the Republic of Suriname (traditionally spelled Surinam by Kazakhstan, also Kazakstan ( Қазақстан, Qazaqstan, qɑzɑqˈstɑn Казахстан, Kazakhstán,) officially the Greece (Ελλάδα transliterated: Elláda, historically, Ellás,) officially the Hellenic Republic (Ελληνική Δημοκρατία S. Geological Survey, Mineral Commodity Summaries, January 2008
Processing
Bauxite is strip mined (surface mining) because it is found at the surface, with little or no overburden. Surface mining is a type of Mining in which soil and rock overlying the mineral deposit are removed Approximately 95% of the world's bauxite production is processed into aluminium. Bauxites are typically classified according to their intended commercial application: metallurgical, abrasive, cement, chemical and refractory.
Bauxites are heated in pressure vessels with sodium hydroxide solution at 150-200 °C through which aluminium is dissolved as aluminate (Bayer process). The Bayer process is the principal industrial means of refining Bauxite to produce Alumina. After separation of ferruginous residue (red mud) by filtering, pure gibbsite is precipitated when the liquor is cooled and seeded with fine grained aluminium hydroxide. Gibbsite is converted into aluminium oxide by heating. This is molten at approx. 1000 °C by addition of cryolite as a flux and reduced to metallic aluminium by a highly energy-consumptive electrolytic process (the Hall-Héroult process). Cryolite ( Na 3 Al[[fluorine F]]6 Sodium hexafluoroaluminate) is an uncommon Mineral identified with the once large deposit An electrolyte is any substance containing free Ions that behaves as an electrically conductive medium The Hall-Héroult process is the major industrial process for the production of Aluminium.
References
- Bardossy, G. (1982): Karst Bauxites. Bauxite deposits on carbonate rocks. Elsevier Sci. Publ. 441 p.
- Bardossy, G. and Aleva, G. J. J. (1990): Lateritic Bauxites. Developments in Economic Geology 27, Elsevier Sci. Publ. 624 p. ISBN 0-444-98811-4
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