Copper Anode Mud Pretreatment Enriched In Gold And Silver The New Technology Research

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.The study was base on raw material of copper anode slime which produced by copper electrolytic refining from some company.The novel process of leachig copper- Leachig lead- removing selenium by roasting - hydrochloric acid leaching was provided to pretreat the copper anode slime.After the process the amount of anode slime was reduced largely and gold and silve were concentrated significantly which would be useful for enhancing the recovery ratio of gold and silve and be helpful for the comprehensive recovery of copper anode slime.This novel process could also reduce the amount of anode slime needed to be roasted,and the production capacity of rotary kiln would be enhanced greatly.The emission of SO₂ would be decreased because of the less consumption of sulfuric acid.The leaching ratio of copper was 99%after the sulfuric acid leaching when leaching temperature was 80℃,nH₂SO₄:nCu was 1.5,liquid-solid ratio was 3:1 and reaction time was 1.5h.Then,the decoppered anode slime was milled with sodium carbonate and leached by nitric acid solution.Compared with the leaching efficiency,the optimum conditions were as follows:milling time was 3h,nNa₂CO₃:nPb was 2.5,liquid-solid ratio was 2:1,ball-to-powder weight ratio was 8:1,nHNO₃:nPb was 6.0,leaching time was 0.5h and leaching temperature was 23℃,the leaching ratio of lead up to 70.2%.Using the hydrochloric acid to leach the delead anode slime after sulfating roasting to remove selenium.The optimum conditions of the hydrochloric acid leaching were as follows: hydrochloric acid amount was 3.0 times,reaction temperature was 18℃, reaction time was 2h,and liquid-solid ratio was 3:1.At these conditions,the leaching ratio of Cu,As and Bi were 45.4%,65.2%and 85.0%,respectively. In this study,the novel process and the traditional process were carried out to pretreat the copper anode slime respectively,and then leaching Au and Ag under the same condition.The results indicated that the novel process was better then the other one.Meanwhile,the elements trends were analysised when using two different processes to treat the anode slime,the results showed that the novel process was better than traditional process.Taking production of copper anodes slime 2000t per year for example,compared to the traditional process,the total value of elements recycled from copper anode slime would be 60,900,000 Yuan higher and the amount of SO₂ discharged would be 20t fewer when used the novel process to treat the copper anode slime.