江西石坞金矿床地质特征和金的赋存状态及对选矿工艺的指示意义

Geological Characteristics and Gold Occurrence State and Its Indicative Significance for Mineral Processing Technology in Shiwu Gold Deposit,Jiangxi Province

石坞金矿床位于钦杭结合带东段北部万年推覆体中金山推覆构造的中部位置,矿体严格受次级韧性剪切带控制,矿石类型主要为糜棱岩和超糜棱岩型。利用光学显微镜观察、X射线衍射(X-ray diffraction,XRD)分析、化学成分分析、扫描电镜(scanning electron microscope,SEM)分析等手段,对石坞金矿床矿石特征及金矿物的赋存状态进行研究。结果表明,矿石中金属矿物以黄铁矿为主,次为毒砂,粒径范围0.04~0.4 mm。脉石矿物以石英为主,金矿物只有自然金一种。金矿物的赋存状态以裂隙金(64.92%)和粒间金(23.99%)为主。按粒度分类,以细粒金(57.24%)和微粒金(27.01%)为主,粒径范围0.005~0.037 mm。在0.074 mm的磨矿细度达到75%的情况下通过全硫化物浮选,可以较好地对金矿物进行富集和回收。通过选矿工艺对比研究,“快速浮选-快浮尾矿再浮选”的选矿工艺的金回收率最高,达到93.89%。

The Shiwu gold deposit is located in the middle of Jinshan nappe structure in Wannian nappe in the northern part of the eastern section of the Qinzhou-Hangzhou junction belt.The ore body is strictly controlled by secondary ductile shear zone,and the ore types are mainly mylonite and ultra mylonite type.The characteristics of the ore and the occurrence state of gold minerals in the Shiwu gold deposit were studied by light microscope observation,X-ray diffraction analysis(XRD),chemical composition analysis,scanning electron microscope analysis(SEM).The research shows that the metal minerals is mainly pyrite,followed by arsenopyrite,with a particle size range of 0.04 mm to 0.4 mm.The gangue minerals are mainly quartz,and the gold mineral is only native gold.The occurrence state of gold mineral is mainly fissure gold(64.92%)and intergranular gold(23.99%).Classified by particle size,it mainly consists of grained gold(57.24%)and microgranular gold(27.01%),with a particle size range of 0.005 mm to 0.037 mm.When the grinding fineness reaches 75%at 0.074 mm,full sulfide flotation can effectively enrich and recover gold minerals.Through comparative research on beneficiation processes,the final gold recovery rate of the“fast flotation-fast flotation tailings re-flotation”beneficiation process is the highest(93.89%).