甘肃全鑫金矿矿石难浸原因初探

Reason for the difficult leaching of the Quanxin gold deposit, Gansu

全鑫金矿为变质碎屑岩型金矿床,矿化类型可分为含金石英脉和破碎蚀变岩型。通过对矿石的工艺矿物学性质的研究,矿石的Au含量一般在1×10-6～4×10-6之间,并含有C有机,As,属C As型金矿石。矿石中金属矿物主要为褐铁矿、赤铁矿及黄钾铁钒,金矿物以含银自然金为主,自然金与褐铁矿关系十分密切,常以包裹体形式嵌布于其中,粒度一般为0 002mm左右。筛分后,不同粒级矿样的Au含量不同,在小于0 037mm粒级中,Au含量达4 72×10-6,分布率高达93 42%。经过小型工业堆浸试验,呈现出周期较长、浸出率较低的特征。其原因是金的单体解离和暴露不充分,浸矿液中的氰化物难以与所有的金粒发生作用。同时,矿石中石墨、C有机及其他一些粘土矿物也促使含Au溶液中的Au发生沉淀,造成浸出率降低。

The Quanxin gold deposit is metamorphic detrital rock type gold deposit, its mineralized types include auriferous quartz vein type and fractured altered rock type. The study on the technical mineralogy character of ore shows that the Au content is 1×10^(-6)～4×10^(-6), and contents organic carbon and As, is the C-As type gold ore. Limonite and pyrite are the main carrier mineral of Au and limonite has closer relation with Au. Gold mineral is mainly Ag-bearing nature gold and always insert in limonite as micrograined-fine inclusion, the grain size is usually about 0.002 mm. After sizing, different size fraction sample has different Au content and less than 0.037 mm the Au content can reach 4.72×10^(-6), the distributing ratio is 93.42%. The minor-scale industrial heap-leaching test presents the character of long leaching cycle and low leaching ratio. The reason is the solitary liberation and insufficiency exposure of Au; this has made the reaction difficult between cyanide (in the leaching fluid) and all gold grain. At the same time, the existence of graphite, organic carbon and other clay mineral are made Au in the auriferous fluid birth into precipitation and the Au leaching ratio declined.