从湿法炼锌厂滤饼中选择性浸出回收镉

Recovery of cadmium from hydrometallurgical zinc smelter by selective leaching

研究了一种简单的从电解锌流程中产生的Cd-Cu-Zn滤饼中选择性回收镉的湿法工艺。镉的浸出、过滤和再浸出常规流程需多个阶段,成本较高。此研究的目的是寻找一种更简单的方法从电解锌流程锌净化阶段的Cu-Cd滤饼中回收镉。所研究的流程包括从Cu-Cd滤饼中除去锌,选择性浸出镉和通过去除Fe、Tl和Co,净化之后再进行电解和熔铸。Cu-Cd滤饼中的锌通过两个阶段转移至液相中,铜和镉在滤饼中富集。在较高的固液质量体积比条件下从滤饼中选择性浸出镉,溶液中镉的浓度较高。在特殊条件下选择性浸出镉可使富镉溶液中共同沉淀的杂质最少。浸出反应在铜的溶解开始时停止。用KMnO_4和NaOH氧化和沉淀杂质,如Fe、Tl和部分Co。净化后的硫酸镉溶液通过电积得到阴极镉,然后熔铸得到99.95%的金属镉。整个流程中,镉总回收率为70%～72%。

A hydrometallurgical process for the recovery of cadmium was developed through a simple flowsheet of selective cadmium leaching from the Cd-Cu-Zn cake generated in electrolytic zinc circuit.This research work relates to development of a simpler process approach for the recovery of cadmium in an electrolytic zinc circuit from the copper-cadmium cake of zinc purification section.The overall cadmium recovery of this process flowsheet was found to be 70～72%.