Mercury (element): Difference between revisions

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Line 111: Mercury is an extremely rare element in the earth's crust, having an average crustal abundance by mass of only 0.08 parts per million. However, because it does not blend [[geochemistry\|geochemically]] with those elements that comprise the majority of the crustal mass, mercury ores can be extraordinarily concentrated considering the element's abundance in ordinary rock. The richest mercury ores contain up to 2.5% mercury by mass, and even the leanest concentrated deposits are at least 0.1% mercury (12,000 times average crustal abundance). This makes mercury ore the most easily depleted of all metal ores. Depletion of mercury ores has been a major concern since the 1960s and it is now almost certain that the last mineable deposits were discovered in [[Algeria]] in the mid-1970s. Since the early 1970s, total world production of mercury has fallen from 9,000 [[tonne]]s to 1,600 tonnes due to depletion of reserves. It is found either as a native metal (rare) or in [[cinnabar]], [[corderoite]], [[livingstonite]], and other [[mineral]]s with cinnabar (Hg[[sulfur\|S]]) being the most common ore. Mercury ores usually occur in very young orogenic belts where rock of high density are forced to the crust of the Earth, often in hot springs or other [[volcano\|volcanic]] regions. Most present-day production occurs in [[Spain]], [[Kyrgyzstan]], [[China]] and [[Tajikistan]]. Over 100,000 tons of mercury were mined from the region of [[Huancavelica]], [[Peru]], over the course of three centuries following the discovery of deposits there in 1563; mercury from Huancavelica was crucial in the production of silver in colonial Spanish America. Many former ores in [[Italy]], [[Slovenia]], the [[United States]] and [[Mexico]] which once produced a large proportion of the world's supply have now been completely mined out. The metal is extracted by heating cinnabar in a current of air and condensing the vapor. The equation for this extraction is :HgS + O<sub>2</sub> → Hg + SO<sub>2</sub>