Bauxite - Wikipedia, The Free Encyclopedia

8/12/2019 Bauxite - Wikipedia, The Free Encyclopedia

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Bauxite with US penny for

comparison

QEMSCAN mineralmaps of bauxite

ore-forming pisoliths

Bauxite in Les Baux-de-Provence,

France

BauxiteFrom Wikipedia, the free encyclopedia

Bauxite, an aluminium ore, is the world's main source of aluminium. It

consists mostly of the minerals gibbsite Al(OH)3, boehmite -AlO(OH)

and diaspore -AlO(OH), mixed with the two iron oxides goethite and

haematite, the clay mineral kaolinite and small amounts of anatase TiO2.

Bauxite was named bythe French geologist Pierre Berthier in 1821 after

the village of Les Baux in Provence, southern France,where he

discovered it and was the first to recognize that it contained aluminium.

Contents

1 Formation

2 Production trends3 Processing

4 See also

5 References

6 Further reading

7 External links

Formation

Lateritic bauxites (silicate bauxites) are distinguished from karst bauxite

ores (carbonate bauxites). The carbonate bauxites occur predominantly

in Europe and Jamaica above carbonaterocks (limestone and dolomite),

where they wereformed by lateritic weathering andresidual accumulation

of intercalated clay layers dispersed clays which were concentrated as

the enclosing limestones gradually dissolved during chemical weathering.

The lateritic bauxites are found mostly in the countries of the tropics.

They were formed by lateritization of various silicate rocks such asgranite, gneiss, basalt, syenite, and shale. In comparison with the iron-rich

laterites, the formation of bauxites depends even more on intense

weathering conditions in a location with very good drainage. This enables the dissolution of the kaolinite and the

precipitation of the gibbsite. Zones with highest aluminium content are frequently located below a ferruginous

surface layer. The aluminium hydroxide in the lateritic bauxite deposits is almost exclusively gibbsite.

In the case of Jamaica, recent analysis of the soils showed elevated levels of cadmium, suggesting that the bauxite

originates from recent Miocene ash deposits from episodes of significant volcanism in Central America.
http://en.wikipedia.org/wiki/File:140606_Les-Baux-12.jpghttp://en.wikipedia.org/wiki/File:140606_Les-Baux-12.jpghttp://en.wikipedia.org/wiki/File:Qemscan_pisoliths.pnghttp://en.wikipedia.org/wiki/Aluminium_hydroxidehttp://en.wikipedia.org/wiki/Lateritehttp://en.wikipedia.org/wiki/Silicate#Silicate_rockhttp://en.wikipedia.org/wiki/Tropicshttp://en.wikipedia.org/wiki/File:140606_Les-Baux-12.jpghttp://en.wikipedia.org/wiki/File:BauxiteUSGOV.jpghttp://en.wikipedia.org/wiki/File:BauxiteUSGOV.jpghttp://en.wikipedia.org/wiki/French_peoplehttp://en.wikipedia.org/wiki/Geologyhttp://en.wikipedia.org/wiki/Pierre_Berthierhttp://en.wikipedia.org/wiki/File:BauxiteUSGOV.jpghttp://en.wikipedia.org/wiki/Haematitehttp://en.wikipedia.org/wiki/Clay_mineralshttp://en.wikipedia.org/wiki/Kaolinitehttp://en.wikipedia.org/wiki/Anatasehttp://en.wikipedia.org/wiki/File:BauxiteUSGOV.jpghttp://en.wikipedia.org/wiki/Diasporehttp://en.wikipedia.org/wiki/Mixturehttp://en.wikipedia.org/wiki/Iron_oxidehttp://en.wikipedia.org/wiki/Goethitehttp://en.wikipedia.org/wiki/File:BauxiteUSGOV.jpghttp://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Gibbsitehttp://en.wikipedia.org/wiki/Boehmitehttp://en.wikipedia.org/wiki/File:BauxiteUSGOV.jpghttp://en.wikipedia.org/wiki/Volcanic_ashhttp://en.wikipedia.org/wiki/Miocenehttp://en.wikipedia.org/wiki/Cadmiumhttp://en.wikipedia.org/wiki/Jamaicahttp://en.wikipedia.org/wiki/Aluminium_hydroxidehttp://en.wikipedia.org/wiki/Iron_oxidehttp://en.wikipedia.org/wiki/Shalehttp://en.wikipedia.org/wiki/Syenitehttp://en.wikipedia.org/wiki/Basalthttp://en.wikipedia.org/wiki/Gneisshttp://en.wikipedia.org/wiki/Granitehttp://en.wikipedia.org/wiki/Silicate#Silicate_rockhttp://en.wikipedia.org/wiki/Lateritehttp://en.wikipedia.org/wiki/Tropicshttp://en.wikipedia.org/wiki/Chemical_weatheringhttp://en.wikipedia.org/wiki/Clayhttp://en.wikipedia.org/wiki/Weatheringhttp://en.wikipedia.org/wiki/Dolomitehttp://en.wikipedia.org/wiki/Limestonehttp://en.wikipedia.org/wiki/Carbonate_rockhttp://en.wikipedia.org/wiki/Jamaicahttp://en.wikipedia.org/wiki/Europehttp://en.wikipedia.org/wiki/Karsthttp://en.wikipedia.org/wiki/Francehttp://en.wikipedia.org/wiki/Provencehttp://en.wikipedia.org/wiki/Les_Baux-de-Provencehttp://en.wikipedia.org/wiki/Pierre_Berthierhttp://en.wikipedia.org/wiki/Geologyhttp://en.wikipedia.org/wiki/French_peoplehttp://en.wikipedia.org/wiki/Anatasehttp://en.wikipedia.org/wiki/Kaolinitehttp://en.wikipedia.org/wiki/Clay_mineralshttp://en.wikipedia.org/wiki/Haematitehttp://en.wikipedia.org/wiki/Goethitehttp://en.wikipedia.org/wiki/Iron_oxidehttp://en.wikipedia.org/wiki/Mixturehttp://en.wikipedia.org/wiki/Diasporehttp://en.wikipedia.org/wiki/Boehmitehttp://en.wikipedia.org/wiki/Gibbsitehttp://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Aluminiumhttp://en.wikipedia.org/wiki/Orehttp://en.wikipedia.org/wiki/File:140606_Les-Baux-12.jpghttp://en.wikipedia.org/wiki/Pisolithhttp://en.wikipedia.org/wiki/QEMSCANhttp://en.wikipedia.org/wiki/File:Qemscan_pisoliths.pnghttp://en.wikipedia.org/wiki/Penny_(United_States_coin)http://en.wikipedia.org/wiki/File:BauxiteUSGOV.jpg


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Bauxite with core of unweathered

rock

One of the world's largest bauxite

mines in Weipa, Australia

Production trends

In 2009, Australia was the top producer of bauxite with almost one-third

of the world's production, followed by China, Brazil, India, and Guinea.

Although aluminium demand is rapidly increasing, known reserves of its

bauxite ore are sufficient to meet the worldwide demands for aluminium

for many centuries.[1]Increased aluminium recycling, which has the

advantage of lowering the cost in electric power in producing aluminium,will considerably extend the world's bauxite reserves.

Numbers for 2010's total proven bauxite reserves x1,000 tonne [2]

Country

Mine production

ReservesReserve

base20102011

(est.)

Guinea 17,400 18,000 7,400,000 8,600,000

Australia 68,400 67,000 6,200,000 7,900,000Vietnam 80 80 2,100,000 5,400,000

Jamaica 8,540 10,200 2,000,000 2,500,000

Brazil 28,100 31,000 3,600,000 2,500,000

Guyana 1,760 2,000 850,000 900,000

India 18,000 20,000 900,000 1,400,000

China 44,000 46,000 830,000 2,300,000

Greece 2,100 2,100 600,000 650,000Iran 500[3]

Suriname 4,000 5,000 580,000 600,000

Sierra Leone 1,090 1,700 180,000 ?

Kazakhstan 5,310 5,400 160,000 450,000

Venezuela 2,500 4,500 320,000 350,000

Russia 5,480 5,800 200,000 250,000

United States 30[3]

N/A 20,000 40,000Other countries 2,630 2,600 3,300,000 3,800,000

World total

(rounded)209,000 220,000 29,000,000 38,000,000

In November 2010, Nguyen Tan Dung, the prime minister of Vietnam, announced that Vietnam's bauxite reserves

might total 11000 Mt; this would be the largest in the world.[4]

Processing
http://en.wikipedia.org/wiki/Vietnamhttp://en.wikipedia.org/wiki/Nguyen_Tan_Dunghttp://en.wikipedia.org/wiki/United_Stateshttp://en.wikipedia.org/wiki/Russiahttp://en.wikipedia.org/wiki/Venezuelahttp://en.wikipedia.org/wiki/Kazakhstanhttp://en.wikipedia.org/wiki/Sierra_Leonehttp://en.wikipedia.org/wiki/Surinamehttp://en.wikipedia.org/wiki/Iranhttp://en.wikipedia.org/wiki/Greecehttp://en.wikipedia.org/wiki/Chinahttp://en.wikipedia.org/wiki/Indiahttp://en.wikipedia.org/wiki/Guyanahttp://en.wikipedia.org/wiki/Brazilhttp://en.wikipedia.org/wiki/Jamaicahttp://en.wikipedia.org/wiki/Vietnamhttp://en.wikipedia.org/wiki/Australiahttp://en.wikipedia.org/wiki/Guineahttp://en.wikipedia.org/wiki/Tonnehttp://en.wikipedia.org/wiki/Electric_powerhttp://en.wikipedia.org/wiki/Aluminium_recyclinghttp://en.wikipedia.org/wiki/Australiahttp://en.wikipedia.org/wiki/Weipa,_Queenslandhttp://en.wikipedia.org/wiki/File:Weipa-bauxite-mine.jpghttp://en.wikipedia.org/wiki/File:Bauxite_with_unweathered_rock_core._C_021.jpg


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Bauxite being loaded at Cabo Rojo, Dominican Republic

to be shipped elsewhere for processing; 2007

Bauxite is usually strip mined because it is almost always found near the surface of the terrain, with little or no

overburden.Approximately 70% to 80% of the world's

dry bauxiteproduction is processed first into alumina,

and then intoaluminium by electrolysis as of 2010.

Bauxite rocks are typically classified according to their

intended commercial application: metallurgical,

abrasive, cement, chemical, and refractory.

Usually, bauxite ore is heated in a pressure vessel alongwith a sodium hydroxide solution at a temperature of

150 to 200C. At these temperatures, the aluminium is

dissolved asan aluminate (the Bayer process). After

separationof ferruginous residue (red mud) by filtering, pure gibbsite is precipitated when the liquid is cooled, and

then seeded with fine-grained aluminium hydroxide. The gibbsite is usually converted into aluminium oxide, Al2O3,

by heating. This mineral is dissolved at a temperature of about 960 C in molten cryolite. Next, this molten

substancecan yield metallic aluminium by passing an electric current through it in the process of electrolysis, which

is called theHallHroult process, named after its American and French discoverers.

Prior to theinvention of this process in 1886, elemental aluminium was made by heating ore along with elemental

sodium orpotassium in a vacuum. The method was complicated and consumed materials that were themselves

expensiveatthat time. This made early elemental aluminium more expensive than gold.[5]

See also

Alcoa

Bauxite, Arkansas

RioTinto AlcanUnited Company RUSAL

References

1. ^"Bauxite and Alumina" (http://minerals.usgs.gov/minerals/pubs/commodity/bauxite/mcs-2012-bauxi.pdf) (PDF)

U.S. Geological Survey. p. 2. Retrieved 9 January 2014.

2. ^"Bauxite and Alumina" (http://minerals.usgs.gov/minerals/pubs/commodity/bauxite/mcs-2012-bauxi.pdf) (PDF)

U.S. Geological Survey (Mineral Commodity Summaries). January 2012. p. 27. Retrieved August 1, 2012.

3. ^ ab"World mineral statistics | MineralsUK" (http://www.bgs.ac.uk/mineralsuk/statistics/worldStatistics.html).

Bgs.ac.uk. Retrieved 2013-10-25.

4. ^"Mining Journal - Vietnams bauxite reserves may total 11 billion tonnes" (http://www.mining-

journal.com/exploration--and--development/vietnams-bauxite-reserves-may-total-11-billion-tonnes). Retrieved

2010-11-28.

5. ^"Aluminium versus aluminum Author: Michael Quinion, 19962011"

(http://www.worldwidewords.org/articles/aluminium.htm). Worldwidewords.org. 2006-01-23. Retrieved 2011-12

19.
http://www.worldwidewords.org/articles/aluminium.htmhttp://www.mining-journal.com/exploration--and--development/vietnams-bauxite-reserves-may-total-11-billion-tonneshttp://www.bgs.ac.uk/mineralsuk/statistics/worldStatistics.htmlhttp://minerals.usgs.gov/minerals/pubs/commodity/bauxite/mcs-2012-bauxi.pdfhttp://minerals.usgs.gov/minerals/pubs/commodity/bauxite/mcs-2012-bauxi.pdfhttp://en.wikipedia.org/wiki/United_Company_RUSALhttp://en.wikipedia.org/wiki/Rio_Tinto_Alcanhttp://en.wikipedia.org/wiki/Bauxite,_Arkansashttp://en.wikipedia.org/wiki/Alcoahttp://en.wikipedia.org/wiki/Goldhttp://en.wikipedia.org/wiki/Vacuumhttp://en.wikipedia.org/wiki/Potassiumhttp://en.wikipedia.org/wiki/Sodiumhttp://en.wikipedia.org/wiki/Hall%E2%80%93H%C3%A9roult_processhttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Cryolitehttp://en.wikipedia.org/wiki/Aluminium_oxidehttp://en.wikipedia.org/wiki/Red_mudhttp://en.wikipedia.org/wiki/Bayer_processhttp://en.wikipedia.org/wiki/Aluminiumhttp://en.wikipedia.org/wiki/Sodium_hydroxidehttp://en.wikipedia.org/wiki/Electrolysishttp://en.wikipedia.org/wiki/Aluminahttp://en.wikipedia.org/wiki/Overburdenhttp://en.wikipedia.org/wiki/Surface_mininghttp://en.wikipedia.org/wiki/Dominican_Republichttp://en.wikipedia.org/wiki/File:CaboRojoDRBauxite.jpg


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Wikimedia Commons has

media related to Bauxite.

Further reading

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, Elsevie

Sci. Publ. 624 p. ISBN 0-444-988

Grant, C; lalor, G and Vutchkov, M (2005) Comparison of bauxites from Jamaica, the Dominican Republic

and Suriname. Journal of Radioanalytical and Nuclear Chemistry p. 385-388 Vol.266, No.3

Hanili, N. (2013).Geological and geochemical evolution of the Bolkardai bauxite deposits, Karaman,

Turkey: Transformation from shale to bauxite. Journal of Geochemical Exploration

External links

USGS Minerals Information: Bauxite

(http://minerals.usgs.gov/minerals/pubs/commodity/bauxite/)

Mineral Information Institute

(http://www.mii.org/Minerals/photoal.html)

"Bauxite".New International Encyclopedia. 1905.

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Categories: Sedimentary rocks Aluminium minerals Bauxite mining

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Bauxite - Wikipedia, The Free Encyclopedia