The Concentration Of Gold And Silver Via The Flotation Process From Copper Anode Slime

The copper anode slime is a kind of by-product produced in the copper electrolytic refining process. Because it contains massive precious metals and other rare elements, being an important raw material to extract precious metals. This thesis took the novel beneficiation technology to concentrate the precious metals from copper anode slime, which provided by Jinchuan group Co., LTD. The different kinds of xanthate collectors were firsly synthesized by homemade methods, and the function mechanism between the collectors and the anode slime were also investigated. In addition, the study applied the hydrometallurgy methods to pretreat copper anode slime, and then collected the metals via flotation process. With these processes, the amount of anode slime reduced largely. Gold and silver were concentrated significantly which would be useful for enhancing the recovery ratio of gold and silver. And it is also helpful for the comprehensive recovery of copper anode slime.The experimental results show that the synthetic productivity of collectors can reach more than 70% by homemade methods. And the longer carbon chain, the lower product rate. The electrochemical test results of copper anode slime in different collector systems show that the polarization current of anode mud in xanthate system was 1.5 to 20 times as that in phosphate system, indicating that the the former one has the more collect speed. However, the phosphate has the higher collect selectivity, and its tafel slope was only 31.3% of that in xanthate system. The results provide the important evidence for the synthesis and selection of collectors.The composition of copper anode slime was analyzed, and selenium was removed via pretreatment process. The experimental results show that the removal rate of Se can attain above 99% and that of Cu can achieve more than 98%. The prepared collectors were then applied in the rough flotation of copper anode slime. The pH values, collector type, addition order of drugs, and so on, were studied in detail. The experimental results show that, the flotation reagent system of concentration process is similar to roughing flotation, but the quantities of reagents were decreased. The concentration ratio of gold and silver can obtain 2, when PH was control at 2, slurry density was control at 15%, dosages of xanthate were control at two kg/t, dosages of dithiophosphate were control at one kg/t, dosages of sodium hexametaphosphate were control at five kg/t and the homemade collectors were used. The concentrate grade of Ag obtained more than 35%, showing that the concentrate can be directly applied to the following casting process. Hence the handling cost of anode slime can be reduced. The gold grade was boost from 0.3% in raw anode slime to 0.7%～0.8% and recovery rate attained 87.17% in concentrate. The silver grade was boost froml6.32% in raw anode slime to 35.42% and recovery rate attained 95.08% in concentrate. The thesis provides the significant reference to the flotation treatment process of copper anode slime.