| A step-by-step leaching process was used to recover copper, silver and lead from the lead chloride slag generated during the bismuth refining process. Copper was first leached under low acid conditions and separated from lead and silver. Then, the separation of lead and silver was achieved through ammonia leaching. Process experiments were conducted using an optimized scheme. The results showed that in the copper leaching stage, by controlling the initial reaction at pH of 3 and liquid-solid ratio of 5:1, adding 1.1 times sodium sulfate, and leaching at 75 ℃ for 1.5 hours, the copper content in the leaching residue of lead chloride slag could be decreased to 0.1%, and the silver content in the reaction solution was not more than 2 mg/L. In the silver leaching stage, by controlling the ammonia concentration at 7%, and leaching at 50 ℃ for 1.5 hours, the silver content in the leaching could decreased to 100 g/t. The process test indicates that a good comprehensive recovery outcome can be realized by this technique. |
