Method of treating spent electrolytic solution from electrolytic copper production

摘要

Disclosed herein is a method for treating a spent copper- refining electrolyte to remove impurities such as copper (Cu), arsenic (As), antimony (Sb), bismuth (Bi), nickel (Ni) and the like by using a hydrogen sulfide gas. The method comprises the steps of: (a) blowing a hydrogen sulfide gas into the spent electrolyte to precipitate copper sulfide (CuS) ; (b) blowing air into the coprecipitates solution obtained in the above step (a) to oxidize arsenic, bismuth and antimony thereby redissolving them into the solution, and the solution is subjected to solid-liquid separation to separate copper sulfide from the liquid; (c) blowing a sulfur dioxide gas into the copper-depleted liquid to reduce arsenic, bismuth and antimony and blowing a nitrogen gas to purge the remaining sulfur dioxide gas; (d) blowing a hydrogen sulfide gas to precipitate arsenic, bismuth and antimony in the form of sulfides and blowing a nitrogen gas to purge the remaining hydrogen sulfide gas and separating arsenic sulfide (As.sub.2 S.sub.3) from the liquid; and (e) concentrating the liquid to separate crude nickel sulfate (NiSO.sub.4) and sulfuric acid (H.sub.2 SO.sub.4).