Bauxite

Bauxite is a sedimentary rock with a relatively high aluminium content. It is the world's main source of aluminium. Bauxite consists mostly of the aluminium minerals gibbsite (Al(OH)3), boehmite (γ-AlO(OH)) and diaspore (α-AlO(OH)), mixed with the two iron oxides goethite (FeO(OH)) and haematite (Fe2O3), the aluminium clay mineral kaolinite (Al2Si2O5(OH)) and small amounts of anatase (TiO2) and ilmenite (FeTiO3 or FeO.TiO2).[1]

In 1821 the French geologist Pierre Berthier discovered bauxite near the village of Les Baux in Provence, southern France.[2]

BauxiteUSGOV
Bauxite with US penny for comparison
Qemscan pisoliths
QEMSCAN mineral maps of bauxite ore-forming pisoliths

Formation

Bauxite with unweathered rock core. C 021
Bauxite with core of unweathered rock

Numerous classification schemes have been proposed for bauxite but, as of 1982, there was no consensus.[3]

Vadász (1951) distinguished lateritic bauxites (silicate bauxites) from karst bauxite ores (carbonate bauxites):[3]

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.

Production trends

2005bauxite
Bauxite output in 2005
Weipa-bauxite-mine
One of the world's largest bauxite mines in Weipa, Australia

Australia is the largest producer of bauxite, followed by China.[4] In 2017, China was the top producer of aluminium with almost half of the world's production, followed by Russia, Canada, and India.[5] Although aluminium demand is rapidly increasing, known reserves of its bauxite ore are sufficient to meet the worldwide demands for aluminium for many centuries.[6] 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.

2017 total proven bauxite reserves x1,000 Mg[4]
Country Mine production Reserves
Guinea 45,000 7,400,000
Australia 83,000 6,000,000
Vietnam 2,000 3,700,000
Brazil 36,000 2,600,000
Jamaica 8,100 2,000,000
China 68,000 1,000,000
Indonesia 3,600 1,000,000
Guyana 1,500 850,000
India 27,000 830,000
Russia 5,600 500,000
Greece 1,800 250,000
Saudi Arabia 3,900 210,000
Kazakhstan 5,000 160,000
Malaysia 1,000 110,000
United States W[a] 20,000
Other countries 9,030 3,200,000
World total (rounded) 300,000 30,000,000
  1. ^ Withheld to avoid disclosing company proprietary data

In November 2010, Nguyen Tan Dung, the prime minister of Vietnam, announced that Vietnam's bauxite reserves might total 11,000 Mt (11 trillion kg); this would be the largest in the world.[7]

Processing

CaboRojoDRBauxite
Bauxite being loaded at Cabo Rojo, Dominican Republic, to be shipped elsewhere for processing; 2007
Bauxite being digested by washing with a hot solution of sodium hydroxide at 175 °C (347 °F) under pressure at National Aluminium Company, Nalconagar, India.

Bauxite is usually strip mined because it is almost always found near the surface of the terrain, with little or no overburden. As of 2010, approximately 70% to 80% of the world's dry bauxite production is processed first into alumina and then into aluminium by electrolysis.[8] 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 along with a sodium hydroxide solution at a temperature of 150 to 200 °C (300 to 390 °F). At these temperatures, the aluminium is dissolved as sodium aluminate (the Bayer process). The aluminium compounds in the bauxite may be present as gibbsite(Al(OH)3), boehmite(AlOOH) or diaspore(AlOOH); the different forms of the aluminium component will dictate the extraction conditions. The undissolved waste, bauxite tailings, after the aluminium compounds are extracted contains iron oxides, silica, calcia, titania and some un-reacted alumina. After separation of the residue 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 in rotary kilns or fluid flash calciners to a temperature in excess of 1,000 °C (1,830 °F). This aluminium oxide is dissolved at a temperature of about 960 °C (1,760 °F) in molten cryolite. Next, this molten substance can yield metallic aluminium by passing an electric current through it in the process of electrolysis, which is called the Hall–Héroult process, named after its American and French discoverers.

Prior to the invention of this process, and prior to the Deville process, aluminium ore was refined by heating ore along with elemental sodium or potassium in a vacuum. The method was complicated and consumed materials that were themselves expensive at that time. This made early elemental aluminium more expensive than gold.[9]

Source of gallium

Bauxite is the main source of the rare metal gallium.[10]

During the processing of bauxite to alumina in the Bayer process, gallium accumulates in the sodium hydroxide liquor. From this it can be extracted by a variety of methods. The most recent is the use of ion-exchange resin.[11] Achievable extraction efficiencies critically depend on the original concentration in the feed bauxite. At a typical feed concentration of 50 ppm, about 15 percent of the contained gallium is extractable.[11] The remainder reports to the red mud and aluminium hydroxide streams.[12]

See also

References

  1. ^ The Clay Minerals Society Glossary for Clay Science Project Archived 2016-04-16 at the Wayback Machine
  2. ^ P. Berthier (1821) "Analyse de l'alumine hydratée des Beaux, département des Bouches-du-Rhóne" (Analysis of hydrated alumina from Les Beaux, department of the Mouths-of-the-Rhone), Annales des mines, 1st series, 6 : 531-534. Notes:
    • In 1847, in the cumulative index of volume 3 of his series, Traité de minéralogie, French mineralogist Armand Dufrénoy listed the hydrated alumina from Les Beaux as "beauxite". (See: A. Dufrénoy, Traité de minéralogie, volume 3 (Paris, France: Carilian-Goeury et Vor Dalmont, 1847), p. 799.)
    • In 1861, H. Sainte-Claire Deville credits Berthier with naming "bauxite", on p. 309, "Chapitre 1. Minerais alumineux ou bauxite" of: H. Sainte-Claire Deville (1861) "De la présence du vanadium dans un minerai alumineux du midi de la France. Études analytiques sur les matières alumineuses." (On the presence of vanadium in an alumina mineral from the Midi of France. Analytical studies of aluminous substances.), Annales de Chimie et de Physique, 3rd series, 61 : 309-342.
  3. ^ a b Bárdossy, G. (1982). Karst Bauxites. Amsterdam: Elsevier. p. 16. ISBN 978-0-444-99727-2.
  4. ^ a b U.S. Geological Survey, Mineral Commodity Summaries, January 2018 (PDF). U.S. Geological Survey. 2018. pp. 30–31.
  5. ^ https://minerals.usgs.gov/minerals/pubs/commodity/aluminum/mcs-2017-alumi.pdf
  6. ^ "Bauxite and Alumina" (PDF). U.S. Geological Survey. p. 2. Retrieved 9 January 2014.
  7. ^ "Mining Journal - Vietnam's bauxite reserves may total 11 billion tonnes". Archived from the original on 2011-06-16. Retrieved 2010-11-28.
  8. ^ "BBC - GCSE Bitesize: Making aluminium". Archived from the original on 2018-02-25. Retrieved 2018-04-01.
  9. ^ Michael Quinion (2006-01-23). "Aluminium versus aluminum". Worldwidewords.org. Retrieved 2011-12-19.
  10. ^ "Compilation of Gallium Resource Data for Bauxite Deposits Author: USGS" (PDF). Retrieved 2017-12-01.
  11. ^ a b Frenzel, Max; Ketris, Marina P.; Seifert, Thomas; Gutzmer, Jens (March 2016). "On the current and future availability of gallium". Resources Policy. 47: 38–50. doi:10.1016/j.resourpol.2015.11.005.
  12. ^ Moskalyk, R. R. (2003). "Gallium: the backbone of the electronics industry". Minerals Engineering. 16 (10): 921–929. doi:10.1016/j.mineng.2003.08.003.

Further reading

  • Bárdossy, G. (1982): Karst Bauxites: Bauxite deposits on carbonate rocks. Elsevier Sci. Publ. 441 p.
  • Bárdossy, G. and Aleva, G.J.J. (1990): Lateritic Bauxites. Developments in Economic Geology 27, Elsevier Sci. Publ. 624 p. ISBN 0-444-98811-4
  • 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
  • Hanilçi, N. (2013). Geological and geochemical evolution of the Bolkardaği bauxite deposits, Karaman, Turkey: Transformation from shale to bauxite. Journal of Geochemical Exploration

External links

Alumina Limited

Alumina Limited is a public company listed on the Australian Securities Exchange. It was formed in 2003 in a demerger from Western Mining Corporation, and is one of the top 100 companies on the ASX (by market capitalization).

Alumina's only business activity is as the owner of a 40% share in a joint venture with Alcoa called Alcoa World Alumina and Chemicals (AWAC). AWAC's business is the mining of bauxite, the extraction of alumina (aluminium oxide) and the smelting of pure aluminium. It has about 17% of the global alumina market. Alcoa owns the remaining 60% of the business and acts as day-to-day manager.

In Australia, AWAC trades as Alcoa of Australia (AoA), which owns two bauxite mines and three refineries (to extract aluminium oxide from bauxite) in Western Australia and owns a smelter (to extract pure aluminium metal) and has a controlling interest in another in Victoria.

AWAC also has operations or interests in Texas, Suriname, Jamaica, Brazil, Spain, Guinea, and owns Alcoa Steamship.

Alumina's Chief Executive Officer is Mike Ferraro and the board is chaired by Peter Day.

Given that the management of Alumina's assets is performed entirely by other companies, their extensive governance structure and regular board meetings have attracted adverse comment. Internet publication Crikey describe Alumina's board as "corporate Australia's cosiest and most expensive lunch club".Alumina Limited formally delisted from the 'New York Stock Exchange', prior to the opening of trading in February 2014. This was because they were already in an American Stock Exchange (OTC Markets Group). Hence they were only present in the Australian Stock Exchange (ASX).

Bauxite, Arkansas

Bauxite is a town in Saline County, Arkansas, United States. Located within Central Arkansas, the town is named for bauxite, the source ore for aluminium, which was found in abundant quantities in the area and became a source of aluminium refining. The town's population boomed during expanded aluminium production during World War II and shrank rapidly with output of the ore. Bauxite was incorporated as a town in 1973. The population was 487 at the 2010 census.

Bauxite High School

Bauxite High School (BHS) is a comprehensive public high school located in Bauxite, Arkansas, United States. The school provides secondary education in grades 9 through 12 for students encompassing 86.09 square miles (223.0 km2) of land including Bauxite, Tull and nearby Saline County and Grant County communities. It is one of five public high schools in Saline County and the only senior high school administered by the Bauxite School District.

The current high school facilities were built in 2001, replacing a Depression-era Works Progress Administration-built school that was destroyed by fire on 5 January 2001.

Bauxite and Northern Railway

The Bauxite and Northern Railway (reporting mark BXN) is a Class III railroad operating in the United States state of Arkansas. BXN operates over 3 miles (4.8 km) of track in Bauxite, Arkansas. Traffic consists of largely of alumina, and the railroad hauls 4,059 carloads per year. In 2005, the railroad was purchased by holding company RailAmerica. In December 2012, Genesee & Wyoming acquired the railroad in its acquisition of RailAmerica.

Bauxite fibrosis

Bauxite pneumoconiosis, also known as Shaver's disease, corundum smelter's lung, bauxite lung or bauxite smelters' disease, is a progressive form of pneumoconiosis usually caused by occupational exposure to bauxite fumes which contain aluminium and silica particulates.It is typically seen in workers involved in the smelting of bauxite to produce corundum.

Bauxite tailings

Bauxite tailings, also known as red mud, red sludge, bauxite residue, or alumina refinery residues (ARR), is a highly alkaline waste product composed mainly of iron oxide that is generated in the industrial production of alumina (aluminium oxide, the principal raw material used in the manufacture of aluminium metal and also widely used in the manufacture of ceramics, abrasives and refractories). Annually, about 77 million tons of the red special waste are produced, causing a serious disposal problem in the mining industry. The scale of production makes the waste product an important one, and issues with its storage are reviewed and every opportunity is explored to find uses for it.

Over 95% of the alumina produced globally is through the Bayer process; for every tonne of alumina produced, approximately 1 to 1.5 tonnes of bauxite tailings/residue are also produced. Annual production of alumina in 2018 was approximately 126 million tonnes resulting in the generation of over 160 million tonnes of bauxite tailings/residue.

Bayer process

The Bayer process is the principal industrial means of refining bauxite to produce alumina (aluminium oxide) and was developed by Carl Josef Bayer. Bauxite, the most important ore of aluminium, contains only 30–60% aluminium oxide (Al2O3), the rest being a mixture of silica, various iron oxides, and titanium dioxide. The aluminium oxide must be purified before it can be refined to aluminium metal.

Dobrești mine

The Dobrești mine is a large mine in the northwest of Romania in Bihor County, 55 km southwest of Oradea and 629 km north of the capital, Bucharest. Dobrești represents the largest bauxite reserve in Romania having estimated reserves of 10 million tonnes.

Economy of Jamaica

Jamaica has natural resources, primarily bauxite, and an ideal climate conducive to agriculture and also tourism. The discovery of bauxite in the 1940s and the subsequent establishment of the bauxite-alumina industry shifted Jamaica's economy from sugar and bananas. By the 1970s, Jamaica had emerged as a world leader in export of these minerals as foreign investment increased.Weakness in the financial sector, speculation, and lower levels of investment erode confidence in the productive sector. The government continues its efforts to raise new sovereign debt in local and international financial markets in order to meet its U.S. dollar debt obligations, to mop up liquidity to maintain the exchange rate and to help fund the current budget deficit.

Jamaican Government economic policies encourage foreign investment in areas that earn or save foreign exchange, generate employment, and use local raw materials. The government provides a wide range of incentives to investors, including remittance facilities to assist them in repatriating funds to the country of origin; tax holidays which defer taxes for a period of years; and duty-free access for machinery and raw materials imported for approved enterprises.

Free trade zones have stimulated investment in garment assembly, light manufacturing, and data entry by foreign firms. However, over the last 5 years, the garment industry has suffered from reduced export earnings, continued factory closures, and rising unemployment. This may be attributed to intense competition, absence of North American Free Trade Agreement (NAFTA) parity, drug contamination delaying deliveries, and the high cost of operation, including security costs. The Government of Jamaica hopes to encourage economic activity through a combination of privatization, financial sector restructuring, reduced interest rates, and by boosting tourism and related productive activities.

In April 2014, the Governments of Jamaica and China signed the preliminary agreements for the first phase of the Jamaican Logistics Hub (JLH) - the initiative that aims to position Kingston as the fourth node in the global logistics chain, joining Rotterdam, Dubai and Singapore, and serving the Americas. The Project, when completed, is expected to provide many jobs for Jamaicans, Economic Zones for multinational companies and much needed economic growth to alleviate the country's heavy debt-to-GDP ratio. Strict adherence to the IMF's refinancing programme and preparations for the JLH has favourably affected Jamaica's credit rating and outlook from the three biggest rating agencies.

Linden, Guyana

Linden is the second largest city in Guyana after Georgetown, and capital of the Upper Demerara-Berbice region, located at 6°0′0″N 58°18′0″W, altitude 48 metres (160 feet). It was declared a town in 1970, and includes the communities of MacKenzie Christianburg, and Wismar. It lies on the Demerara River and has a population of roughly 29,298 (Bureau of Statistics, Population and Housing Census - 2002, GUYANA). It is primarily a bauxite mining town, containing many mines 60–90 metres deep, with many other pits now in disuse.

List of countries by bauxite production

Bauxite is the most important aluminum ore. This form of rock consists mostly of the minerals gibbsite Al(OH)3, boehmite γ-AlO(OH), and diaspore α-AlO(OH), in a mixture that usually includes the two iron oxides goethite and hematite, and may include the clay mineral kaolinite, and small amounts of the titanium minerals anatase TiO2, Ilmenite, FeTiO3, and FeOTiO2.

Bauxite was named after the village Les Baux in southern France, where it was first recognised as containing aluminium and named by the French geologist Pierre Berthier in 1821.

Maggotty

Maggotty is a settlement in Jamaica. It has a population of 1,335 as of 2009. Maggotty was a Bauxite mining town in the 1960s and 1970s. The Revere Bauxite plant polluted the longest river on the Island of Jamaica, the Black River. The small town also consist of three schools neighboring each other: a high school, Maggotty High school; a primary school, Glen Stuart Primary; and an infant school, Maggotty Basic School.

Mining in Brazil

Mining in Brazil is centered on the extraction of gold, copper, tin, iron and bauxite.

Mining industry of Guinea

The mining industry of Guinea was developed during colonial rule. The minerals extracted consisted of iron, gold, diamond, and bauxite. Guinea ranks first in the world in bauxite reserves and 6th in the extraction of high-grade bauxite, the aluminium ore. The mining industry and exports of mining products accounted for 17% of Guinea’s gross domestic product (GDP) in 2010. Mining accounts for over 50% of its exports. The country accounts for 94% of Africa’s mining production of bauxite. The large mineral reserve, which has mostly remained untapped, is of immense interest for international firms.In recent years, the mining industry in Guinea has suffered from controversy, specifically with respect to the iron ore mining industry and the block of mines in Northern Guinea.

Mining industry of Guinea-Bissau

Mining in Guinea-Bissau is limited to small-scale production of construction materials, such as clays, granite, limestone, and sand and gravel. The country’s prospective minerals include bauxite, diamond, gold, heavy minerals, petroleum, and phosphate rock.

Moengo

Moengo (/ˈmuŋ.ɡo/) is a town in Suriname, located in the Marowijne district, between Paramaribo and the border town Albina. Moengo is also a resort (municipality) in the district of Marowijne. Alcoa's first bauxite mine in Suriname was located in Moengo. In former times it was a major centre for the mining and storage of bauxite. The Moengo Airstrip is one of the oldest airports in Suriname, in use since August 1953, when the Piper Cub (PZ-NAC) of Kappel-van Eyck named "Colibri" landed there from Zorg en Hoop Airport.

Sri Medan

Sri Medan(铁山)is a main town in Batu Pahat District, Johor, Malaysia. Long ago, it was a famous bauxite mine in Johore.

Teluk Ramunia

Teluk Ramunia is a town in Kota Tinggi District, Johor, Malaysia. It is a well-known bauxite mining town in the early days of Malaysia. It is a sight seeing place, good for a family picnic spot. Now it is known for Oil and Gas Fabrication industries.

Weipa, Queensland

Weipa is a coastal mining town in the local government area of Weipa Town in Queensland, Australia. It is the largest town on the Cape York Peninusla. It exists because of the enormous bauxite deposits along the coast. The Port of Weipa is mainly involved in exports of bauxite. There are also shipments of live cattle from the port.In the 2016 census, Weipa had a population of 3,899 people.

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