青海某金矿浮选尾矿工艺矿物学研究

摘要

The average grade of a gold ore in Qinghai province is 2.62 g/t and the arsenic content is 0.28％.The concentrating plant used the flotation process of one stage of rouphing,two stages of cleaning and two stages of scavenging.The recovery of Au is only about 77％ and the loss is serious.In order to find the reason,and to improve the flotation recovery,using the process mineralogy research methods such as the chemical multielement analysis,the optical microscope and the scanning electron microscopy (SEM),a detailed study on the process mineralogy for flotation tailings was carried out.The results show that the flotation tailings has a gold content of 0.81 g/t,but the occurrence state of gold is relatively complex,mainly as very small grains (0.3 ～ 3 μm) wrapped in the gangue minerals such as quartz,calcite,albite,secondly as microgranular (size 2 ～ 6 μm) wrapped in arsenopyrite and rhombic arsenic in lollingite,and also as visible gold particles (particle size less than 10 μm) embedded throughout the gangue fissure.The main reason for the low recovery is the high proportion of fine particle size and wrapped gold.%青海某金矿石平均含金2.62 g/t、含砷0.28％,为典型的含砷难处理金矿.选矿厂采用“一次粗选、两次精选、两次扫选”浮选工艺,但金的回收率仅为77％左右,损失严重.为了查明金损失原因,提高选矿厂浮选回收率,利用化学多元素分析、光学显微镜、扫描电镜等工艺矿物学研究手段,对青海某金矿选矿厂浮选尾矿进行工艺矿物学研究.结果表明,浮选尾矿含金0.81 g/t,但金的赋存状态较为复杂,主要以极微细粒(粒度0.3～3 μm)形式包裹于石英、方解石、钠长石等脉石矿物中,其次是以微细粒(粒度2～6 μm)形式包裹于毒砂和斜方砷铁矿中,还可见部分金粒(粒度小于10 μm)嵌布于脉石裂隙中.金嵌布粒度极细和包裹金所占比例较高,是选矿回收率不高的主要原因.