关于金的表生地球化学行为

On the Hypergene Geochemical Behavior of Gold

金的表生地球行为是一个十分重要的课题。近十几年的研性表明,金并非隋性元素,其化学活动性是很强的。金的原生赋存状态影响着金的表生地球化学行为,呈硫化物、分子和原子分散的金在表生环境中易被活化、近移和富集,而呈自然状态(粒径大于50u)则是不活动的。此外,景观条件对金的表生地球化学行为也有很重要的影响,不同的景观条件下金表现出不同的地球化学行为。生物活动,特别是植物,对金的表生迁移、分配和富集也起着相当重要的作用。地表天然水是金的表生迁移的主要介质。在地表水中,溶解金的含量此颗粒金的含量高2至6倍的这表明,金在天然水中,并非主要以物理形式携迁,在许多情况下是以化学状态迁移的。作者认为,影响金从溶液中沉淀下来的主要因素有:pH值的改变引起金络合物的分解;吸附和共沉淀作用;Eh值的改较;有机络合物的氧化分解;生物的沉淀作用。

The hypergene geochemical behavior of gold is a very important research subject. Studies done last decades suggest that gold is not an inert element, its chemical activity is quite strong, The original occurence of gold affects its hypergene geochemical behavior. The gold dispersing in sulfide or as molecular, atom is easierly activized and thus transported and enriched, whereas natural gold(diameter of gold grain great than 50μ is not active, Besides, landscape can also acts as an important effect factor to the hypergene geochemical behavior of gold, The activities of organisms, especially those of plant, play a considerable role in the transportation, allotment and concentration of gold under hypergene condition, Surface(natural) water is the main medium for the transportation of gold. In surface water dissolved gold is 2 to 6 times than gold grain in content, suggesting that gold is not transported predominantly in physical form but chemically dissolved form in surface water, According to the author, the main factors affecting the precipitation of gold in solution are:change of pH. value which may be able to cause the resolution of gold complex compound; adsorption and co-precipitation; change of Eh value; oxidation of organic complex compound giving rise to decomposition; biologic precipitation.