内蒙白音诺等矿床中方铅矿中银的赋存形式及其与伴生元素锑、铋的关系

The Occurrence State of Silver in Galena in Relation to Antimony and Bismuth in the Baiyinno Deposit, Inner Mongolia

作者根据Ag2S-PbS,Ag2S-PbS-Sb2S3及各体系相平衡资科以及內蒙白音诺等矿床中各种矿物共生组合中方铅矿的成分,论证了银的赋存状态及其与伴生元素锑、铋的关系。在含银及低温条件下,银在方铅矿中形成独立的银锑硫盐矿物,这有利于银的回收。在含铋低温条件下,银在方铅矿中不可避免地有相当一部分呈固溶体的状态分散在晶格中,它不利于银的回收。因此,只需研究银的赋存状态及矿石或方铅矿中伴生元素锑、铋含量及其比例,即可对铅精矿中银的存在形式及回收率作出初步的评价。

On the basis of sulfide phase equilibria of the systems Ag_2S-PbS, Ag_2SPbS-Sb_2S_3 and Ag_2S-PbS-Bi_2S_3, and electron microprobe analyses of galena from various mineral assemblages in some deposits of Inner Mongolia, the authors discuss the occurrence state of silver and its enrichment pattern in galena in relation to Sb and/or Bi contents. In Sb-bearing geochemical environments and under low temperature conditions (<350℃), silver tends to form fine-grained, independent Ag-Sb-sulfosalt minerals in galena which much favors the recovery of silver in the course of ore-processing. In Bi-bearing geochemical environments and under low temperature conditions, however, silver tends to be disseminated in galena as an isomorphous substitute for Pb, which renders its recovery from the ore difficult or even impossible. In the Baiyinno deposit where native bismuth and Bi-sulfosalts were formed under hydrothermal conditions, silver exists as independent sulfosalts in the galena matrix and as an isomorphous substitute for Pb in galena. The recovery of silver in these deposits is therefore low. Electron microprobe analysis of galena from these deposits indicate low silver content of galena coexisting with Sb-sulfosalts but high silver content of galena coexisting with native bismuth and Bi-sulfosalts.