多孔Pb合金阳极在电积制备铜粉中的应用特性

Application characteristics of Pb-alloy porous anode in copper powder electrowinning

为了降低电积法生产铜粉的能耗,减小阳极腐蚀率,提高阴极铜粉品质,采用反重力渗流技术制备不同合金成分、不同孔径的多孔Pb合金阳极,并与平板阳极在阳极电位、阳极腐蚀率、阳极氧化膜的形貌与组成、阴极铜粉的纯度和形貌等方面进行对比。结果表明:多孔阳极可以降低阳极真实电流密度,从而降低析氧过电位,如孔径1.0-1.25 mm的Pb-Ag多孔阳极的析氧过电位比同样合金成分平板阳极的降低了131 mV,可以显著降低铜粉电积过程的能耗。另外,多孔阳极表面氧化膜由疏松的粉末状变为致密、平整的片状,提高了阳极的耐腐蚀性能,可以降低阴极铜粉中的Pb含量,有利于提升产品品质。

In order to reduce the energy consumption of copper powder electrowinning, enhance the corrosion resistance of anode and improve the product quality, the Pb-based porous anodes with different pore sizes and various Ag and Ca contents were prepared by counter-gravity infiltration, and compared with plate anodes in following aspects： anodic potential, anodic corrosion rate, morphology and composition of the anodic oxidation film, purity and morphology of cathodic product. The results show that the porous anode can reduce the real anodic current density and decrease anodic oxygen evolution overpotential. For example, the oxygen evolution overpotential of Pb-Ag porous anode （pore diameter of 1.0-1.25 mm） is 131 mV lower than that of Pb-Ag plate anode, which can significantly decrease the energy consumption. Besides, the anodie oxidation film of porous anode changes from loose, powdery form into denser, flatter flaky form, which can enhance the anodic corrosion resistance, reduce the Pb content of copper powder and then improve the product quality.