某浮选金精矿浸出工艺优化试验研究

Experimental Study on Optimization of Leaching Technique for Gold Concentrate from Flotation

某浮选金精矿氰化浸出尾渣中Au品位1.58 g/t、Ag品位49.88 g/t,为了探索尾渣中目标矿物解离特征以及金、银未充分浸出的原因,对该浸渣开展了系统性工艺矿物学分析,结果表明,浸渣中裸露金含量占63.85%,这部分金在氰化浸出过程中属于可回收金;浸渣中有36.15%的金以包裹体形式存在,磨矿细度较粗是导致金金属流失的原因。在工艺矿物学研究基础上进行了浸出条件优化试验,确定适宜的金精矿浸出条件为:磨矿细度-0.037 mm粒级占95%、矿浆浓度50%、氰化钠浓度5 g/L、浸出时间36 h、溶氧度4.6 mg/L。在此条件下Au浸出率为99.30%,较现场生产提高1.73个百分点;银平均浸出率为64.41%,较现场生产提高24.41个百分点。

The residue after cyanide leaching of some flotation gold concentrate grades 1.58 g/t Au and 49.88 g/t Ag.In order to explore the liberation characteristics of the target minerals in the residue and the reasons for the Au and Ag that aren′t fully leached out,a systematic process mineralogical analysis was performed for the leaching residue.It is found that the leaching residue contains 63.85%of bare gold,which can be recovered from the cyanide leaching process,36.15%of the gold in the residue exists in the form of inclusion,and the coarser grinding fineness contributes to the losses of this part of gold.Based on the analysis of process mineralogy,an optimization experiment was carried out,and the appropriate leaching conditions for gold concentrate were determined,including the grinding fineness of-0.037 mm 95%,the pulp concentration of 50%,the concentration of sodium cyanide at 5 g/L,the leaching time of 36 h and the dissolved oxygen concentration 4.6 mg/L.In comparison with the on-site production,it is shown that the leaching process under the above conditions can result in the leaching rate of Au up to 99.30%,increased by 1.73 percentage points,and the average leaching rate of silver up to be 64.41%,increased by 24.41 percentage points.