Bauxite mining in Australia

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Bauxite deposit near Weipa

The bauxite mining in Australia is favored by the large deposits , this made Australia the largest producer of bauxite with 71.5 million tons in 2010 and in 2009 this country was the fifth largest producer of aluminum . Aluminum is made from bauxite. In Australia there are five large mines in which bauxite is mined , seven aluminum oxide refineries that process the bauxite into aluminum oxide using the Bayer process , and six aluminum smelters that use large-scale industrial facilities for smelting electrolysis to produce aluminum with high energy consumption.

The bauxite deposits being mined are in Western Australia , Queensland and the Northern Territory ; undeveloped deposits in the Mitchell Plateau and Cape Bougainville areas in Western Australia, Cape York Peninsula in Queensland and central New South Wales .

In 2008, 80 percent of the aluminum produced in Australia was exported and the economically exploitable resources are estimated at 6.2 gigatons .

The sale of aluminum is considered to be an economic indicator of the world economy, for example the worldwide aluminum production fell by more than 10 percent in the following year as a result of the financial crisis in 2008. Aluminum is mainly used in aircraft, engine and lightweight construction.

history

Aluminum processing in Australia began in 1914 with die casting from imported aluminum. Aluminum cables for electrical applications were manufactured here from 1922.

It was not until the 1930s that industrial production expanded. In 1936 the Australian Aluminum Company was founded near Grainville near Sydney , which limited itself to the manufacture of military equipment. In April 1941 the Australian government decided to achieve independence from foreign aluminum supplies and issued a license to build an aluminum smelter. The first aluminum smelter was the Bell Bay Aluminum Smelter in Tasmania , construction of which began in 1948 and which produced the first aluminum ingot in September 1955. In the first year of production, a total of 9,000 tons of aluminum were produced, but the bauxite required for this came from Malaysia and Indonesia .

Bauxite was discovered in the Darling Range in Western Australia back in the early 1940s. In the 1950s, more large bauxite deposits were discovered, which aroused worldwide interest. The company Western Australia Mining explored one of these large bauxite deposits and the Jarrahdahle bauxite mine in 1963 from Alcoa World Alumina and Chemicals opened (AWAC) industrial-scale than the first bauxite mining in Australia.

The Bell Bay aluminum smelter in Tasmania was the first ever industrial aluminum smelter to be built in the southern hemisphere when it was founded in 1955 as a joint venture between the Australian and Tasmanian governments. In the first year of production, 1,200 tons of aluminum were produced. In 1960 Comalco Industries Pty Limited took over this aluminum smelter, a company that later became Rio Tinto Alcan .

In 1955, geologists discovered the large deposits of bauxite on the Gove Peninsula in the Yolngu Aboriginal reservation near Weipa in Queensland. By the Comalco Act of 1957 the status of the reserve was lifted and the Jarrahdahle bauxite mine received a mining license on 5,760 km² of the Aboriginal reservation on the west coast of the Cape York Peninsula . The bauxite mining began in 1960. The Yolngu did not agree to this law and the mining in their area. Later it turned out that the Aborigines were not involved in the bill, but that the government had only negotiated with representatives of the local Aboriginal mission station in Yirrkala . In 1963, the liberal-conservative government of Robert Menzies decided that mining should be allowed. The Yolngu then turned against the construction of a bauxite mine on their traditional land with the Yolngu Bark Petition , which they wrote on a tree bark in 1963. Later there were further contractual regulations that made further bauxite mining possible and that take into account the interests of the Aborigines in mining and involve them.

Interest in the Australian bauxite deposits increased in the 1970s because oil became more expensive and this was mainly used to generate electrical energy for aluminum production. In the search for cheaper alternatives, Australia's power generation system with coal-fired power plants was the obvious choice.

In 2010 AWAC produced between 10 and 11 percent of the world's alumina production.

Deposits

The volume of Australian bauxite production in 2010 was 71.5 million tons.

The top five bauxite mines in 2010 were the Boddington ( BHP Billiton ), Wollowdale and Huntly (both Alcoa World Alumina and Chemicals ) in Western Australia, Gove in the Northern Territory and Weipa bauxite mines (both Rio Tinto Alcan ) in Queensland. The mines are operated by international mining groups.

There were long protests against the construction of the bauxite mines in the Darling Range in Western Australia and, in the second half of 1979, strong resistance from nature and environmentalists.

The bauxite deposits on the Gove Peninsula and near Weipa in Queensland have an aluminum mineral content of almost 50 percent and are therefore among the deposits with the highest content. In the deposits of Western Australia, which are located in the Darling Range and on the Mitchell Plateau , which has not yet been developed for mining , the content is relatively low at around 30 percent.

Most Australian deposits have a high content of silica , which requires a higher proportion of sodium hydroxide in the production, which increases the production costs and exacerbates the disposal problem. On the other hand, these deposits are close to the surface, are relatively easy to develop in terms of mining and are inexpensive to operate.

The six Australian aluminum smelters produced 1.94 million tons of aluminum in 2010, of which 1.69 million tons were exported.

Emergence

Bauxite is the most abundant ore in the earth's crust and the mineral form of aluminum. In order to produce aluminum from bauxite, the bauxite, which is present in mineral form, has to be extracted into aluminum hydroxide by digestion in caustic soda in the Bayer process . Subsequently, aluminum oxide is produced by removing the water through firing, sintering or calcining, which is processed into aluminum in aluminum smelters with high energy consumption in the Hall-Héroult process .

The bauxites occurring in Australia are described in geology as laterite bauxites, which were formed by lateritic weathering of various silicate rocks such as granite , gneiss , syenite , clay and slate . In this mineralogical-chemical process, rocks on the earth's surface are deeply decomposed under the influence of high temperatures and precipitation, whereby the minerals in the parent rock are largely dissolved. In the weathering phase, the easily soluble elements sodium , potassium , calcium , silicon (silica) etc. are washed out by the seeping rainwater and the poorly soluble elements iron and aluminum accumulate.

In Australia, bauxite was formed in weathered rocks as a pisoid with an average size of about 5 millimeters. The bauxite layers, which normally reach a thickness of 3 to 5 meters in Australia , are about half a meter below the topsoil.

environment

The Australian bauxite deposits that are mined are located a short distance from Australia's coasts. The aluminum smelters are located directly on the coast, where there is also sufficient energy available, which is necessary for the production of aluminum on a large scale. For example, Alcoa of Australia operates three refineries near populated areas. It is the Pinjarra , Kwinana, and Wagerup alumina refineries that make alumina. In these plants, finely ground bauxite is mixed with concentrated caustic soda in the Bayer process at around 7 bar and around 180 ° C, which, in addition to high energy consumption, can also lead to environmental pollution.

Since electrical energy is mainly generated by coal-fired power stations in Australia, there is further environmental pollution. For example, Alcoa's two smelting electrolysis plants in the Portland aluminum smelter in western Victoria and Point Henry aluminum smelter in Geelong consume 18 to 25 percent of the electrical energy in the entire state of Victoria. In these plants, aluminum oxide is melted with the addition of cryolite as a flux at around 1000 ° C and produced in electrolysis cells with high energy input to aluminum in the Hall-Héroult process , a melt-flow electrolysis.

If there are no processing plants for the ore on the mine site, the ore is transported on railways, trucks or conveyor belts. In Western Australia, for example, this is done on a 51-kilometer conveyor belt from the Boddington bauxite mine to the Worsley alumina refinery .

The Point Henry smelter of Alcoa World Alumina and Chemicals Australia at the Corio Bay in Geelong in Victoria

In addition to the energy expenditure and the heat that escapes from processing bauxite for aluminum production, the mining of bauxite consumes large areas of land that have to be recultivated. This can be achieved by dumping the original topsoil and then reusing it for recultivation. When the mined bauxite is dissolved, basic red mud is formed , which must be dumped and safely stored. Red mud contains caustic caustic soda , toxic heavy metal oxides and about one percent heavy metal hydroxides. The toxic components like fluorides , arsenates , chromates and vanadates can be washed out of the sludge. The aluminum ions are harmful to microorganisms and toxic to animals and plants. Red mud landfills should therefore be covered on their surface and have no contact with groundwater. During the production of aluminum, fluorine and hydrogen fluoride escape , which cannot be entirely avoided, and carbon monoxide (CO) and carbon dioxide (CO 2 ) are released.

Residents in the Wangerup refinery area, particularly those at Yarloop , have long complained of health problems and illnesses that they believe are caused by air pollution.

Overview

Bauxite mines

The five bauxite mines in Australia, sorted by state, are (as of 2010):

Alumina refineries

The seven alumina refineries, sorted by state, are (as of 2010):

Aluminum smelters

The six aluminum smelters, sorted by state, are (as of 2010):

Others

There are also twelve extrusion mills for ore processing and two aluminum rolling mills in Australia.

In Australia, the Aluminum Council is the umbrella organization for aluminum producers that looks after their interests. According to this association, 16,700 people (2009: 13,000) and 2,900 contract workers (2009: 4,400) were employed in aluminum production in 2010.

Individual evidence

  1. ↑ a b c d aluminum.org.au : Australian Bauxite , in English, accessed April 5, 2012
  2. ↑ ga.gov.au ( Memento of the original from June 2, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 2.0 MB): Paul Kay: Bauxite : In: Australia's Identified Mineral Resources 2009 , in English, accessed on April 5, 2012  @1@ 2Template: Webachiv / IABot / www.ga.gov.au
  3. ↑ a b c tomago.com.au ( Memento of the original from March 17, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. : History in Australia . (English) Retrieved April 13, 2012, last January 12, 2016.  @1@ 2Template: Webachiv / IABot / www.tomago.com.au
  4. ↑ a b alcoa.com : Jaradahle , in English, accessed on April 6, 2012
  5. ↑ riotintoalcan.com : Bell Bay , called in English, 12 April 2012
  6. ↑ australia.gov.au ( Memento of the original from March 24, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. ; Bark petitions: Indigenous art and reform for the rights of Indigenous Australians , in English, accessed April 5, 2012 @1@ 2Template: Webachiv / IABot / australia.gov.au
  7. ↑ riotintoalcan.com : Weipa , in English, accessed April 6, 2012
  8. ↑ alcoa.com : Overview , in English, accessed on April 9, 2012
  9. ↑ researchrepository.murdoch.edu.au (PDF; 6.9 MB): Ron Chapman: Fighting for the Forest. A History of The West Australian Forest Protest Movement 1975-2001 , pp. 132 ff., In English, accessed on April 14, 2012
  10. ↑ world-aluminium.org ( Memento of the original from March 24, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. : Geology of Bauxite , in English, accessed April 6, 2012 @1@ 2Template: Webachiv / IABot / www.world-aluminium.org
  11. ↑ tiotintoalcan.com : Making Aluminum , in English, accessed April 6, 2012
  12. ↑ theage.com.au : william Birnbauer, Jason Dowling: Greenhouse showdown over smelter , May 21, 2006, in English, April 7, 2012
  13. ↑ Frank Muster: Rotschlamm. Residual material from aluminum oxide production - ecological backpack or input for production processes? kassel university press GmbH, Kassel 2007, ISBN 978-3-89958-359-5
  14. ↑ chemieunterricht.de : Extraction and use of aluminum , in English, accessed on April 6, 2012
  15. ↑ perthnow.au ( Memento of the original dated August 13, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. : John Flint: A 5KM buffer zone around the refinery - as the Health Department wants - would wipe Yarloop, Hamel and Cookernup off the map , in English, accessed April 9, 2012  @1@ 2Template: Webachiv / IABot / www.perthnow.com.au
  16. ↑ abc.net.au ( Memento of the original dated November 12, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. : Quentin McDermott: Something in the air , broadcast March 10, 2005, in English, accessed April 9, 2012 @1@ 2Template: Webachiv / IABot / www.abc.net.au
  17. ↑ alumina / australian-aluminum aluminum.org.au : Aluminum , in English, accessed on April 14, 2012
  18. ^ Aluminum.org.au : Alumina , in English, accessed April 14, 2012
  19. ↑ aluminum.org.au ( Memento of the original from March 21, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. : About Us , accessed April 14, 2012  @1@ 2Template: Webachiv / IABot / aluminum.org.au
  20. ↑ aluminum.org.au : Industry Description , in English, accessed on April 14, 2012