Study On Comprehensive Recovery And Utilization Of Tin From Copper Anode Slime

China is the biggest producer and consumer of copper in the world, and annual production of cathode copper exceeds six million tons, and the production of copper anode slime silver-separated residue is more than tens of thousands of tons. Silver-separated residue contain lead, tin, silver and other valuable metals, especially as the increase of the capactity of copper scrap, the content of tin in silver-separated residue is increasing. Thus, it’s siganifcant to recycle these from silver-separated residue. Therefore, the study on recycling tin from copper anode slime silver-separated residue has theoretical value and practical significance.Based on consulting pertinent literature, according to the composition of silver-separated residue and the metallurgical theory, the process of "chloride leaching of lead and silver-alkali fusion transition-water leaching of tin-evaporation crystallization"process was proposed. Results showed that the process can separate tin effectively from silver-separated residue, and at the same time the lead and silver are recycled. The technology has some advantages, such as the flow is short, the device is simple, the process is easy to be handled, and the economic benefit is prominent,which lays a solid theoretical foundation for the recovery of valuable metals from silver-separated residue.The major research contents are as follows:1. The experiment on the chloride leaching of lead and silver was undertaken and the influences of concentration of hydrochloric acid, concentrations of sodium chloride, liquid-solid ratio, temperature, reaction time on leaching rate of lead and silver were alse investigated. Experimental results show that lead and silver could be leached together and recycled respectively in the NaCl-CaCl2-HCl system. The optimal conditions is:the initial concentration of NaCl is260g·L-1, the liquid-solid ratio is11:1, the extractive temperature is80℃, the initial concentration of HCl1.0mol·L-1, the reaction time is1.5hours, the CaCl2quality is1time of theoretical amounts.The leaching rate of lead is99.1%and silver is97.8%.2. The process of "alkali fusion transition-water leaching of Sn" was studied, and the influences of the NaOH quality, roasting temperature, roasting time, liquid-solid ratio, water leaching time, water leaching temperature and water leaching time on the leaching rate of tin were alse investigated. Results show that SnO2in the residue can be transformed to Na2SnO3, which is soluble in water.①The optimal of condition of alkali fusion is:the temperature is800℃, the NaOH quality is3times of theoretical amounts times and the roasting time is2hours.②The optimal of condition of water leaching is:the temperature is25℃, the liquid-solid ratio is2:1and the leaching time is2hours. Under the condition, the leaching rate of Sn can reach90%. 3. The experiment on the purification of the sodium stannate solutions, and the evaporative crystallization were studied. Results show that the purification technology is effective, for which of the lead and copper can be removed easily by using Na2S and the antimony can be removed by the tin powder. Subsequently, the purified Na2SnO3product can be made by evaporator crystallization technology.