甘肃某高硫高砷微细粒金矿石工艺矿物学研究

Study on Process Mineralogy of High Sulfur and Arsenic Fine Gold Ore in Gansu

甘肃某地金矿石为典型的高硫高砷微细粒型难处理金矿石,为探明其工艺矿物学特性,采用化学多元素分析、矿物自动分析系统(MLA)、扫描电子显微镜(SEM)、能谱分析仪(EDS)等分析手段对化学组成、矿物组成、粒度组成、矿物赋存状态及嵌布特征等方面对矿石进行了研究。结果表明:矿石中主要含有Si、Fe、As、S、Au、Ag等元素,其中Au品位为3.75 g/t、Ag品位为110 g/t,具有综合回收价值;S含量为12.53%,As含量为8.40%。矿石中主要金属矿物有毒砂、黄铁矿等;非金属矿物主要为石英。金以自然金的形式存在且粒度微细,经统计的颗粒全部为显微金。外形形态主要以角粒状为主,其次为长角粒状;自然金多包裹于硫化物中(以黄铁矿为主,少量为毒砂),少量分布于黄铁矿裂隙中;矿石中银主要以独立矿物自然银、自然金存在,并嵌布于黝铜矿裂隙中。结合工艺矿物学研究结果综合分析得出结论:该矿石的分选难点在于自然金粒度微细、原矿中含有大量毒砂、自然金主要以包裹金形式存在、黄铁矿和毒砂嵌布密切、含有易泥化矿石。基于以上研究结果,推荐采用氧化焙烧—氰化浸出工艺进行分选。本文从矿物学的角度对甘肃某地高硫高砷金矿石进行了剖析,为该种类型矿物的高效开发利用提供了理论指导。

The gold ore in Gansu province is a typical refractory gold ore with high sulfur and arsenic content.In order to explore its process mineralogy characteristics,The chemical composition,mineral composition,grain size composition,occurrence state and distribution characteristics of minerals were studied by means of chemical multielement analysis,automatic mineral analysis system(MLA),scanning electron microscope(SEM)and energy dispersive spectrometer(EDS).The results show that the ore mainly contains Si,Fe,As,S,Au,Ag and other elements,with Au grade of 3.75 g/t and Ag grade of 110 g/t,which have comprehensive recovery value.S content is 12.53%,As content is 8.40%.The main metal minerals in the ore are toxic sand,pyrite,etc.The non-metallic minerals are mainly quartz.The gold exists in the form of natural gold and the particle size is fine.All the statistical particles are microscopic gold.The shape is mainly angular granular,followed by long angular granular;The natural gold is mostly wrapped in sulfide(mainly pyrite,a small amount of arsenopyrite),and a small amount is distributed in the pyrite fissure.The silver in the ore mainly exists as independent minerals,natural silver and natural gold,and is embedded in the fissures of tetrahedrite.Combined with the results of process mineralogy,it is concluded that the difficulty of the separation of the ore is that the natural gold particle size is fine,the raw ore contains a large amount of arsenopyrite,the natural gold mainly exists in the form of wrapped gold,the pyrite and arsenopyrite are closely embedded,and the ore is easily muddied.Based on the above research results,the oxidation roasting-cyanide leaching process is recommended for separation.In this paper,the gold ore with high sulfur and arsenic content in a certain place of Gansu Province is analyzed from the mineralogical point of view,which provides theoretical guidance for the efficient development and utilization of this kind of mineral.