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Bauxite
Bauxite is a heterogeneous material composed primarily of one or more
aluminium hydroxide minerals, plus various mixtures of silica, iron
oxide, clay, titania, aluminosilicate, and other impurities in minor or
trace amounts. Because it is a mixture of minerals, bauxite itself is
not a mineral but a rock.
Bauxite is reddish-brown, white, tan and tan-yellow.
85% of all the bauxite mined in the world is converted to aluminium
metal, the remaining 15% is consumed in the non-metallurgical sector.
Around two thirds of this is refined via the Bayer process*, a wet
chemical caustic leach method, to make speciality aluminas such as
aluminium hydroxide, calcined aluminas, activated aluminas, etc. That
leaves some 5% of total production which is used directly in industries
such as refractories, abrasives, cement and steel industries.
The aluminium metal is produced from alumina by passing an electric
current through it in a process called "electrolytic
reduction”.
*In the Bayer process, found in 1888 by the German chemist Karl Bayer,
the bauxite is washed with a hot solution of sodium hydroxide at
250°C. This converts the alumina, a pure aluminium oxide, to
aluminum hydroxide, which dissolves in the hydroxide solution. The
other components of bauxite do not dissolve and can be filtered out as
solid impurities.
After this first step, the hydroxide solution is cooled, and the
aluminum hydroxide dissolved in it precipitates out as a white, fluffy
solid. When then heated to 1050°C, the aluminum hydroxide
decomposes to alumina, giving off water vapor in the process.
Links:
-World
Bureau of Metal Statistics - Statistics 2000 - 2003
-EAA-The
European Aluminium Association,
-The International Aluminium Institute
World Bauxite Production
Thousand tonnes
| |
2004
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2005
|
2006
|
2007
|
2008 |
| Europe |
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|
| Albania |
0 |
0 |
0 |
0 |
0 |
| Bosnia - Herzegovina |
916.900 |
1.031.600 |
854.800 |
800.500 |
860.000 |
| Croatia |
1.482 |
500 |
600 |
101 |
500 |
| France |
170.000 |
170.000 |
160.000 |
160.000 |
160.000 |
| Germany |
0 |
0 |
0 |
0 |
0 |
| Greece |
2.396.065 |
2.495.100 |
2.284.380 |
2.093.433 |
2.064.909 |
| Hungary |
647.000 |
535.000 |
507.400 |
515.100 |
511.300 |
| Romania |
150.000 |
170.000 |
0 |
0 |
0 |
| Russia |
6.017.600 |
6.409.300 |
6.399.200 |
6.503.000 |
6.000.000 |
| Serbia & Montenegro |
610.000 |
672.300 |
659.400 |
667.100 |
671.800 |
| Turkey |
365.836 |
356.480 |
771.227 |
863.404 |
900.000 |
| Yuogoslavia |
0 |
0 |
0 |
0 |
0 |
| total |
11.274.883 |
11.840.280 |
11.636.207 |
11.602.638 |
11.168.509 |
| |
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| Africa |
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| Ghana |
585.600 |
726.600 |
885.800 |
748.200 |
694.000 |
| Guinea |
18.795.500 |
19.237.300 |
18.783.800 |
18.519.000 |
18.500.000 |
| Mozambique |
12.000 |
9.518 |
11.800 |
9.000 |
9.000 |
| Sierra Leone |
0 |
0 |
1.001.000 |
1.100.000 |
945.100 |
| total |
19.393.100 |
19.973.418 |
20.682.400 |
20.376.200 |
20.148.100 |
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| Asia |
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| China |
17.518.000 |
17.408.200 |
18.981.000 |
20.446.000 |
21.600.000 |
| India |
11.284.900 |
12.385.400 |
13.940.200 |
20.298.000 |
19.737.000 |
| Indonesia |
1.330.800 |
1.370.610 |
1.501.937 |
1.251.147 |
1.152.000. |
| Iran |
366.000 |
437.595 |
500.000 |
500.000 |
520.000 |
| Kazakhstan |
4.705.400 |
4.815.400 |
4.884.000 |
4.962.600 |
5.160.000 |
| Malaysia |
2.040 |
4.735 |
91.806 |
156.800 |
275.069 |
| Pakistan |
4.800 |
6.500 |
6.829 |
19.005 |
36.000 |
| Viet Nam |
20.000 |
55.000 |
60.000 |
80.000 |
80.000 |
| total |
35.211.940 |
36.428.440 |
39.965.772 |
47.713.552 |
48.560.069 |
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| America |
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| Brazil |
20.958.800 |
20.307.400 |
22.836.300 |
24.754.000 |
28.097.500 |
| Colombia |
480 |
460 |
400 |
0 |
0 |
| Guyana |
1.503.400 |
1.675.842 |
1.453.000 |
2.239.000 |
2.109.000 |
| Suriname |
4.087.108 |
4.756.998 |
4.945.400 |
5.273.195 |
5.333.000 |
| United States |
259.900 |
121.200 |
631.000 |
128.742 |
89.600 |
| Venezuala |
5.814.700 |
5.815.200 |
5.927.800 |
5.021.800 |
5.300.000 |
| total |
32.624.388 |
32.677.100 |
35.793.900 |
37.416.737 |
40.929.100 |
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| Oceania |
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| Australia |
56.593.000 |
59.469.000 |
62.307.000 |
62.428.000 |
63.789.000 |
| total |
56.593.000 |
59.469.000 |
62.307.000 |
62.428.000 |
63.789.000 |
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| Caribbean |
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| Jamaica |
13.296.500 |
14.116.400 |
14.865.354 |
14.567.738 |
14.636.100 |
| total |
13.296.500 |
14.116.400 |
14.865.354 |
14.567.738 |
14.636.100 |
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| WORLD TOTAL |
233.707.799 |
241.271.556 |
255.402.487 |
195.202.665 |
199.230.878 |
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