Study On The Recovery Of Copper And Zinc From High Chlorine Smelting Ash

Since the reform and opening up, along with the development of our country economy by leaps and bounds, on the one hand, we’ve beening faced with a severe non-ferrous metal resources shortage of raw materials and in short supply situation, on the other hand, in the process of non-ferrous metal smelting, will produce a large number of smelting ash containing valuable metals. If these smelting ash can be effectively recycled, so to alleviate the resources crisis, reduce environmental pollution will be of great advantage. In order to effect-ively solve this problem, a hydrometallurgical recovery process was researched to treat the high chlorine smelting ash from a smelter in this subject on the basis of summarizing the existing process methods. The main technological process includes pre-dechlorination, selective leaching, purification, copper electrod-eposition, zinc evaporation crystallization, from which high purity cathode copper and industrial grade zinc sulfate are extracted.Two-stage pre-dechlorination process of washing by sodium carbonate solution after wash was used to treat the ash. The total dechlorination rate is 64.78%. The slag of pre-dechlorination was selectively leached with sulfuric acid, which achieves the separation of copper, zinc and lead, tin, the enrichment of lead and tin. The leaching rates of copper and zinc are 96.17% and 82.69%, respectively. A purification process of impurity was researched on the acid leaching solution. The method of oxidation-neutralization-coprecipitation was used to remove As and metal impurities in the acid leaching solution. The removal rates of arsenic and iron are 96.95% and 89.73%, respectively, furthermore, impurity concent-ration reaches the follow-up process requirement. The methods of N-235 extraction and zinc dust replacement were comparatively studied on the depth dechlo-rination effect of the acid leaching solution. The dechlorination rates are 93.5% and 98.98%, respectively. But the reextraction effect of N-235 extraction method is poor. The process of copper electrodeposition was researched to recover copper from purification solution, then the method of evaporation crystallization was used to extract zinc from the electric effusion. Through the above processes, the cathode copper is obtained with good sheet view quality and purity being greater than 98.16%. The as-obtained product of zinc mainly is ZnSO4·H2O characterized with X-ray diffraction, whose all indexes accord with qualified product requirements of industrial zinc sulfate standard HG/T2326-2005.