氨浸法从冶锌铁渣中回收锌制备活性氧化锌

RECOVERY OF ZINC FROM IRON DREGS BY AMMONIA LEACHING METHOD AND PREPARATION OF ACTIVE ZINC OXIDE

采用氨配合法一次性浸出含锌铁渣中的锌,并用硫化铵对浸出液进行除杂,再将浸出液经蒸氨并加入NH3HCO3制备成活性氧化锌,以完成对锌的回收与利用。采用曲面响应法探讨温度、时间、液固比和氨浓度对锌浸出率的影响,并得到最佳条件如下:浸出温度为20℃、浸出时间为1.7h、液固比为4.4mL/g、氨浓度为8.2%。结果表明:在最佳条件下,锌的浸出率可达99.78%。除杂过程的Cu、Cd去除率均可达95%以上。经检测,活性氧化锌的性能符合化工行业标准HG/T2572—2012《活性氧化锌》要求。

Zn element from solid waste containing zinc was leached one-step by ammonia complex method, and then ammonium sulfide was added to remove impurities in leaching solution.The zinc-ammonia leaching solution was purified and reacted with ammonium bicarbonate to produce active zinc oxide, thus the zinc resources recovery was completed.Response surface methodology was applied to optimize the process of ammonia leaching zinc, the effects of reaction temperature, reaction time, liquid-solid ratio and ammonia concentration, on the leaching rate of zinc were discussed.Experimental results showed that the Zn leaching rate reached 99.78%, under the optimum conditions of reaction temperature of 20 ℃, reaction time of 1.7 h, liquid to solid ratio of 4.4 mL/g and ammonia concentration of 40%.The removal rate of Cu and Cd all exceeded 95% in the purification process.The quality of evaluation on active zinc oxide could meet the requirements of China’s industrial emission standard (HG/T 2572 -2012).