| Tungsten was produced by de Elhuyar brothers, students of Bergman in 1783. They named the new metal wolfram, after the mineral wolframite in which tungsten oxide was found. Miners of 1416 centuries noticed that roasting of the ore tales the tin away, transferring it into slag. They called the ore "wolf's froth" which then was converted into wolfram. Agricola in 1546 named it as Lupi spuma, which meant wolf's foam; in German "wolf rahm". Miners said about tungsten that it "eats" tin as a wolf eats sheep. In 1781 Karl Wilhelm Scheele analyzed white mineral, named tungsten later named scheelite, CaWO4, the name of element which has been accepted I English. |
Tungsten occurs mostly as complex oxidized compounds composed by WO3 and iron or manganese, calcium, copper, lead, thorium and, sometimes, rare earth elements oxides. Wolframite is the most abundant mineral. It is a solid solution of iron and manganese tungstates (wolframates) mFeWO4xnMnWO4 which are salts of tungstic (wolframic) acid. Tungsten ores are associated with granites. Mai deposits are located in China, Myanmar, USA, Bolivia and Portugal, as well as in Ural, Caucasus and Transbaikalia regions of Russia.
Large wolframite and scheelite crystals are very rare. Usually they are found only as inclusions in granites with the average tungsten concentration around 1...2%. |