从热滤渣中富集贵金属的实验研究

针对含贵金属热滤渣物料的物相及元素组成, 提出了氧化焙烧脱硫-硫酸选择性浸出贱金属铜和镍富集贵金属工艺, 讨论了物料粒度、焙烧时间、焙烧温度、硫酸浓度、浸出时间、浸出温度等因素对贵金属富集比的影响。获得最佳工艺参数为: 热滤渣粒度0.080~0.106 mm, 焙烧时间6 h, 焙烧温度700 ℃, 硫酸浓度45%, 浸出时间5 h, 浸出温度95 ℃。在此条件下, 脱硫率达到98.89%, 铜、镍浸出率分别为98.33%和98.12%, 硫酸浸出渣中Au含量1 198.60 g/t, Ag含量1 807.79 g/t, Pt含量1 801.27 g/t, Pd含量1 937.66 g/t。从原料到硫酸浸出渣, 贵金属富集比达到14.19倍。该工艺流程操作简单、富集比高、回收率高、成本低, 可为从热渣中富集贵金属提供借鉴作用。

Experimental Study on Enriching Precious Metals from Hot Residue

A process for concentrating precious metals through oxidizing roasting desulphurization and sulfuric acid selective leaching of base metal copper and nickel was proposed according to the phase and element composition of hot residue materials containing precious metals. A discussion was made on the effects of particle size, roasting time, roasting temperature, sulfuric acid concentration, leaching time and leaching temperature on the enrichment ratio of the precious metals. The optimal process parameters were obtained as follows: grain size of 0.080~0.106 mm, roasting time of 6 h, roasting temperature of 700 ℃, sulfuric acid concentration of 45%, leaching time of 5 h and leaching temperature of 95 ℃. Under this condition, the desulfurization rate was 98.89%, leaching rate of copper and nickel at 98.33% and 98.12% respectively, Au, Ag, Pt and Pd contents in the leaching residues of 1 198.60 g/t, 1 807.79 g/t, 1 801.27 g/t and 1 937.66 g/t respectively, leading to an enrichment ratio of 14.19 for the precious metals from the raw material to the sulfuric acid leaching residue. This process is characterized by simple operation, high enrichment ratio, high recovery and low cost, which can provide a reference for enriching precious metals from hot residues.