旋流电解提取铜冶炼污泥模拟浸出液中有价金属研究

Extracting of Valuable Metal in Simulated Leaching Solution of Sludge from Copper Smelting Process with Cyclone Electrowinning

配制模拟铜冶炼污泥的硫酸浸出液作为电解原液,考察了旋流电解技术分离提取溶液中Cu,Zn,Ni 3种有价金属的效果。结果表明,旋流电解可以实现3种有价金属的分步电解分离,实验中直接获得了电解铜和电解锌产品。对于Cu,Zn,Ni混合溶液的旋流电解过程,Cu优先在阴极电解,电解铜产品以铜粉为主,另含有少量的铜片;电流密度越大,Cu的沉积速度越快,在电流密度为0.04 A·cm-2时,30 min内Cu的回收率达到54.4%;由于Cu的电阻率较低,因此其在阴极上的沉积可以提高系统的导电性,从而使槽电压下降,降低能耗。对于Zn,Ni混合溶液的旋流电解过程,Zn优先于Ni电解,在阴极得到形貌较好的Zn板;槽电压随运行时间下降较电解铜时更加缓慢,30 min内仅下降9.1%;电解产品上部有Ni沉积,且表面由于氢的析出产生类似月球表面环形山的椭圆坑;旋流电解槽内部的旋流流态加之镍的特殊超电势使得Zn优先于Ni电解。

Simulated sulfate leaching solution of sludge from copper smelting process was prepared as electrolyte to investigate the performance of cyclone electrowinning in the separation and extraction of Cu, Zn and Ni from solution. The results showed that three valuable metals could be extracted step by step with cyclone electrowinning. Electrolytic copper and electrolytic zinc were produced. For the process of cyclone electrowinning of mixed solution containing Cu, Zn and Ni, Cu was the first to precipitate in negative electrode. The electrolytic copper products basically consisted of copper powder, as well as a little copper plate. The electrodeposition rate of Cu increased with current density. The recovery rate of 54.4% for Cu was achieved in 30 min at current density of 0.04 A .cm-2 With the depositing of Cu on surface of negative electrode, the conductivity of the system was improved because of the low resistivity of Cu. So, the energy could be saved due to the decrease of cell voltage. For the process of cyclone electrowinning of mixed solution containing Zn and Ni, Zn electrodeposition was prior to Ni. Excellent morphology of Zn plate was obtained in negative electrode. The cell voltage decreased by 9.1% in 30 min. The decrease amplitude was less than that in the process of Cu electrodeposition. A little Ni deposited in the upper half region of the electrolytic zinc product. Owing to the reduction of hydrogen, elliptical hole, which was similar to the crater on the surface of moon, appeared on the surface of electrolytic product. The flow pattern of solution in the electrolytic cell and special overpotential of Ni were considered to be related with the preferential electrodeposition of Zn.