青海某难处理含砷金矿石工艺矿物学研究

青海某难处理含砷金矿矿石性质较为复杂，产出的金精矿金品位及回收率均较低。为充分掌握矿石性质、提高金品位及回收率，利用偏光显微镜、场发射扫描电子显微镜（SEM）等手段对矿石进行了系统 的工艺矿物学研究。结果表明：①不同矿区金品位分布极不均匀，平均Au品位3.0 g/t；矿石中主要金属矿物为黄铁矿，少量闪锌矿和方铅矿以及微量黄铜矿，并且含有少量毒砂，主要非金属矿物为石英和长石，以及 部分绿帘石、透辉石、绢云母、方解石。②矿石中金矿物主要为含量81.58%的银金矿，其余为含量14.80%的自然金与含量3.62%的金银矿；矿石中金矿物颗粒细小，细粒金占93.39%，微粒金占6.64%，最大粒径为31 μ m，最小粒径为2 μm，平均粒径为10 μm；金矿物的赋存状态有包裹金、晶隙金和裂隙金3种，包裹金占79.30%，晶隙金占12.76%，裂隙金占7.94%；金矿物的形态以圆粒状为主，其余为长条状与不规则状。③矿石中 主要载金矿物为黄铁矿和少量毒砂，相比理想黄铁矿中铁含量，矿石中普通黄铁矿与载金黄铁矿中Fe含量分别低2.06个百分点和2.66个百分点，表现出低铁高硫的特征；普通毒砂与载金毒砂中的Fe、As含量相较于理 想含量低，其中普通毒砂Fe、As含量分别低1.65个百分点、3.30个百分点；载金毒砂Fe、As含量分别低0.50个百分点、6.15个百分点，普通毒砂与载金毒砂中S含量分别比理想含量高4.28个百分点和6.65个百分点。④ 矿石中主要载金矿物为黄铁矿，且金的粒度为微细粒，建议通过细磨提高黄铁矿的单体解离度，同时强化黄铁矿的捕收，以进一步增加金的回收率。

Process Mineralogy Study of a Refractory Arsenic-containing Gold Ore in Qinghai

The ore properties of a refractory arsenic-containing gold ore in Qinghai is complex， and the grade and recovery rate of the produced gold concentrate are low. In order to fully grasp the ore properties and improve the gold grade and recovery rate， the process mineralogy of the ore was studied systematically by means of polarizing microscope and field emission scanning electron microscope （SEM）. The results showed that: ①The distribution of gold grade in different mining areas is extremely uneven， and the average gold grade is 3.0 g/t. The main metallic minerals in the ore are pyrite， a small amount of sphalerite and galena，trace chalcopyrite and a small amount of arsenopyrite. The main non-metallic minerals are quartz and feldspar， as well as part of epidote， diopside， sericite and calcite. ② The main non-metallic minerals in the ore are the electrum of 81.58%， the rest are the natural gold of 14.80% and the kustelite of 3.62%. The gold mineral particles in the ore are fine with the maximum particle size of 31 μm and the minimum particle size of 2 μm，in which the average particle size is of 10 μm. The contents of the fine and minuteness gold are accounting for 93.39% and 6.64%， respectively. The occurrence of gold minerals can be divided into the three types of encapsulated gold， interstitial gold and fissure gold with 79.30% of encapsulated gold， 12.76% of interstitial gold and 7.94% of fissure gold. The morphology of gold minerals is mainly round granular， and the rest are long strip and irregular. ③The main gold-bearing minerals in the ore are pyrite and a small amount of arsenopyrite. Compared with the iron contents in ideal pyrite， the iron contents in common pyrite and gold-bearing pyrite in the ore is 2.06 percentage point and 2.66 percentage point lower， respectively， showing the characteristics of low iron and high sulfur. The contents of iron and arsenic in common arsenopyrite and gold-bearing arsenopyrite were lower than ideal ones， and the contents of iron and arsenic in common arsenopyrite were 1.65 percentage point and 3.30 percentage point lower， respectively. The contents of iron and arsenic in gold-bearing arsenopyrite are 0.50 percentage point and 6.15 percentage point lower， respectively. The contents of sulfur in common arsenopyrite and gold-bearing arsenopyrite are 4.28 percentage point and 6.65 percentage point higher than that in ideal arsenopyrite， respectively. ④ The main gold-bearing mineral in the ore is pyrite and the gold particle size is micro-fine. It is suggested to improve the monomer disintegration degree of pyrite and strengthen the collection of pyrite to further increase the recovery rate of the gold.