Salar de Uyuni
(or Salar de Tunupa) is the world's largest salt flat at 10,582 square kilometers (4,086 sq mi). It is located in the Potosí and Oruro departments in southwest Bolivia, near the crest of the Andes, and is elevated 3,656 meters (11,995 ft) above the mean sea level. The Salar was formed as a result of transformations between several prehistoric lakes. It is covered by a few meters of salt crust, which has an extraordinary flatness with the average altitude variations within one meter over the entire area of the Salar. The crust serves as a source of salt and covers a pool of brine, which is exceptionally rich in lithium. It contains 50 to 70% of the world's lithium reserves, which is in the process of being extracted.
Underneath the surface of the Salar is a lake of brine 2 to 20 meters (7 to 66 ft) deep. The brine is a saturated solution of sodium chloride, lithium chloride and magnesium chloride in water. It is covered with a solid salt crust with a thickness varying between tens of centimeters to a few meters. The center of the Salar contains a few "islands", which are the remains of the tops of ancient volcanoes which were submerged during the era of lake Minchin. They include unusual and fragile coral-like structures and deposits that often consist of fossils and algae.
The Salar contains large amounts of sodium, potassium, lithium and magnesium (all in the chloride forms of NaCl, KCl, LiCl and MgCl2, respectively), as well as borax. Of those, lithium is arguably most important as it is a vital component of many electric batteries. With estimated 5,400,000 tonnes (5,300,000 long tons; 6,000,000 short tons), Bolivia holds about half of the world's lithium reserves; most of those are located in the Salar de Uyuni. Lithium is concentrated in the brine under the salt crust at a relatively high concentration of about 0.3%. It is also present in the top layers of the porous halite body lying under the brine; however the liquid brine is easier to extract, by boring into the crust and pumping out the brine.
The brine distribution has been monitored by the Landsat satellite and confirmed in ground drilling tests. Following those findings, an American-based international corporation has invested $137 million to develop lithium extraction. However, lithium extraction in the 1980s and 1990s by foreign companies met strong opposition of the local community. Despite their poverty, locals believed that the money infused by mining would not reach them. There is currently no mining plant at the site, and the Bolivian government doesn't want to allow exploitation by foreign corporations. Instead, it intends to build its own pilot plant with a modest annual production of 1,200 tonnes (1,200 long tons; 1,300 short tons) of lithium and to increase it to 30,000 tonnes (30,000 long tons; 33,000 short tons) tonnes by 2012.
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