熔炼低品位电子废料中铜的湿法冶金选择性回收

摘要

A comparison of three hydrometallurgical methods for selective recovery of copper from low-grade electric and electronic wastes was reported. Scraps were smelted to produce Cu−Zn−Sn−Ag alloy. Multiphase material was analyzed by SEM−EDS and XRD. The alloy was dissolved anodically with simultaneous metal electrodeposition using ammoniacal and sulfuric acid solutions or leached in ammonia−ammonium sulfate solution and then copper electrowinning was carried out. This resulted in the separation of metals, where lead, silver and tin accumulated mainly in the slimes, while copper was transferred to the electrolyte and then recovered on the cathode. The best conditions of the alloy treatment were obtained in the sulfuric acid, where the final product was metal of high purity (99% Cu) at the current efficiency of 90%. Ammoniacal leaching of the alloy led to the accumulation of copper ions in the electrolyte and further metal electrowinning, but the rate of the spontaneous dissolution was low. Anodic dissolution of the alloy in the ammonia−ammonium sulfate solution led to the unfavorable distribution of metals among the slime, electrolyte and cathodic deposit.%比较从低品位电工电子废料中选择性回收铜的3种湿法冶金方法。首先将废料熔炼成Cu−Zn−Sn−Ag合金，并采用SEM−EDS和XRD进行表征。对合金进行阳极溶解，首先采用氨溶液和硫酸溶液对合金进行电沉积或在氨−硫酸铵溶液中浸出，然后进行电沉积铜。实现了各种金属分离，Pb、Ag 和Sn等沉积在阳极泥中，而铜则转移至电解液中并在阴极上还原析出。最佳的处理条件为在硫酸溶液中浸出，获得的最终产品为高纯Cu(99%)，电流效率为90%。采用氨浸出可使Cu离子富集在电解液中，利于后续的电沉积，但是自发溶解的速率较低。在氨−硫酸铵溶液中进行阳极溶解不利于各种金属在阳极泥、电解液和阴极沉积物进行分离。