The Study And Process Design For Comprehensive Utilization Of Zinc Smelting Slag

In recent years, the rapid growth of zinc smelting industry in China cause it's total output ranked first in the world in consecutive years, However, in the rapid development of the production of zinc,the deal with the zinc smelting slag is a problem and has been more serious. The limiting to traditional technology and management lead to dumped waste, occupation of land, environmental pollution, and waste of resources. But the waste also contains a lot of valuable metals, which can become the two important resources.Therefore, comprehensive utilization of the waste of valuable metal is a very important task in the environmental protection work in nonferrous metal industry.In this paper, we use the zinc leaching residue as raw material, and discuss the comprehensive utilization of the gold, silver, indium, sulfur and iron. The optimum conditions determined by single factor test are as follows: 1) Calcination test: calcination temperature: 700? , Calcination time : 2.0 h, the amount of CaC12: 6%; 2) Alkaline leaching experiment of silicon:the ratio of liquid to solid: 4:1, Alkali leaching temperature:120 ?, the concentration of sodium hydroxide: 12 mol/L, Alkali leaching time: 2.0 h; 3)Silver leaching experiment:the ratio of liquid to solid: 3:1, gold leaching agent: 0.5 %,sodium sulfite is 0.09 mol/L, ammonia concentration is 0.8 mol/L, the concentration of copper sulfate: 0.038 mol/L, pH? 11, leaching time: 6 h.Gold, silver, indium recovery rate was as high as 96.90%, 89.38% and 95.65% in the above conditions, and sulfur utilization rate has reached 71.12%, which can be absorped by sodium carbonate solution and then made of sodium sulfite. The iron oxide content of the final product in iron oxide red reached 82.50%, which reached the national standard of type B requirements. On the whole, the experimental realization of the comprehensive utilization of zinc leaching residue.In this paper, the annual processing capacity of 9000 tons of zinc leaching residue comprehensive utilization process design project. Firstly, we carried out the unit operations in various stages of material balance based on technological process, drew the material flow chart(PFD), At the same time, the typical heat exchange equipment had been carried out on the heat balance; Secondly, we carried out the equipment selection according to the material and heat balance,We also determined the types and summaried the main equipment list; the design of the control scheme for the typical equipment was also made out. At the same time ,we drew the piping and instrumentation diagrams (P&ID);Finally, we completed the layout design of the workshop equipment.