| 中国含镓矿床的主要成因类型 |
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| 引用本文：.1982.Chief genetical types of Gallium-bearing deposits in China[J].Mineral Deposits,1(1):51~60 |
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| Chief genetical types of Gallium-bearing deposits in China |
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| Abstract:Gallium is a typical trace element. A systematic study of the gallium content of rocks and ores might bring to light its geochemical behaviourduring the formation of rocks and ores. Taking rocks and ores in Chinaas examples, this paper has established a variety of rocks and minerals with heightened gallium and has elucidated the behaviour of gallium invarious processes of endogenic and exogenic cycles. From the data availableg some general rules can be clearly seen: gallium content increasesfrom ultrabasic rocks to acid rocks with its highest content observed inalkaline rocks, (but in contrast to the general tendency, some increasedamount of gallium is occasionally noticed in basic rocks); pegmatitesare richer in gallium than their parent intrusive rocks; skarns containsmaller quantities of gallium; there exists a noticeable gallium accumulation in greisens and alkaline-metasomatites; a large portion of galliumgoes into hydrothermal sphalerite and alunite; bauxites of weatheringand sedimentary origin are especially rich in gallium; gallium may alsobe present in the sedimentary iron ores and coal ashes; and the regional metamorphic rocks, for example, migmatites, are generelly poorer in gallium than the primary rocks. According to geochemical studies and the formation conditions the gaIlium-bearing deposits in China can be divided into 13 chief genetic types,namely, vanadiferous magnetite-ilmenite deposits, nepheline-containingalkaline complexes, granitic pegmatites, alkaline pegmatites, greisens, Nb,Ta-bearing alkaline-metasomatic granites, Pb-Zn sulphide deposits,copper-pyrite deposits, alunite deposits, bauxites deposits ofweatheringand sedimentary origin, sedimentary and sedimentary-metamorphosed iron ores as well as coal deposits. No independent galliumore bodies have so far been found in China,because gallium is scarce and is widely dispersed in earth, it does notform independent minerals during the formation of ore deposits. The distribution of gallium is dominantly attributable to its close relationship with Al, Zn and, to a less extent, Fe3+. These associations find their expression in the fact that gallium occurs frequently as an accessory constituent associated with Al, Zn, Fe3+ in many common minerals. Ores or rocks with heightened gallium are now used as industrial sources of gallium in China. The metal is recovered as a by-product during the metallurgical treatment of the gallium-bearing ores.The most important gallium-bearing ores in China are bauxites of sedimentary origin and hydrothermal sphalerites. Compared with these minerals, all the other gallium-bearing ores have less practical value. The extraction of gallium fromsuch gallium-rich materials as iron ores and coal ashes have been recently proved to be profitable. |
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