金矿床中黄铁矿-毒砂-辉锑矿标型及金的赋存状态——以湖南省金矿床为例

TYPOMORPHIC CHARACTERISTICS OF PYRITE-ARSENOPYRITE-ANTIMONITE AND OCCURRENCE OF GOLD IN GOLD DEPOSIT:A case study of the gold deposits in Hunan Province

湖南及类似地区的金矿床,金高度富集在黄铁矿、毒砂和辉锑矿中.这些载金的硫(砷)化物具有各自特征性的标型.由于黄铁矿、尤其是毒砂中的金大多属于质点小于0.1μm的不可见金,不仅在光学显微镜下无法找到,即使利用电子探针和在高倍电镜下进行金的特征X射线扫描亦未发现金矿物富集区.由此引起了这类矿物中的金是呈超微细粒形式存在,还是以类质同像存在于其矿物晶格中的不同看法.所以,研究黄铁矿和毒砂的标型特征,查明金的赋存状态,对金的利用十分重要.经有关矿床多项实验研究及选矿试验结果,认为黄铁矿与毒砂中的不可见金,除次显微金外主要应为"纳米金"(矿物金),而非晶格金(结构金).

In the gold deposits in Hunan Province and other similar regions,gold is highly enriched in pyrite,arsenopyrite and antimonite.These gold-bearing sulfides（arsenides）have typical typomorphic characteristics.Most of the gold in pyrite and,especially,in arsenopyrite is invisible,as particles less than 0.1 μm.As a result,the gold cannot be seen in optical microscope.Even if by the electron microprobe and high-power X-ray scanning,the gold mineral concentration is not found.This raises divergence of views about the occurrences of gold in such minerals,i.e.ultramicro particles or isomorphs in mineral lattices.Therefore the study on the typomorphic characteristics of pyrite and arsenopyrite and the occurrence of gold is importance for the utilization of gold.Based on experiments and ore-dressing results in related gold deposits,the invisible gold in pyrite and arsenopyrite is considered to exit as nanometer gold（mineral gold）,but not lattice gold（structure gold）.