LK-C2从废线路板酸性浸出液中萃取回收铜

Selective solvent extraction of copper from acid leaching solution of PCBs with LK-C2

以LK-C2为萃取剂,从废弃线路板酸性浸出液中选择性萃取回收铜,分别研究杂质阳离子、阴离子、pH值、萃取时间、萃取剂浓度和相比(O/A)对萃取效果的影响。结果表明:采用LK-C2从废线路板酸性浸出液中可选择性萃取分离铜,铜/铁分离系数超过2000,溶液中锌和锡几乎不被萃取;随萃取平衡pH值的增大,铜的萃取率升高;随萃取剂在有机相中浓度增加和相比增加,铜回收率增大;阴离子NO3-、SO42-和Cl-对萃取无明显影响。萃取剂每从溶液中萃取1mol铜,将置换2mol氢离子。室温下LK-C2萃取铜的最佳工艺条件:LK-C2体积浓度为15%,相比O/A为1:1,水相初始pH为2.00,萃取时间为10min。在优化条件下,一级萃取率达99.78%;用2.00mol/L硫酸溶液对负载有机相进行反萃,经三级逆流反萃,铜的反萃率达到97.51%。

Copper was extracted with LK-C2 from acid leaching solution of waste printed circuit boards. The effects of pH of aqueous solution, reaction time, concentration of LK-C2 and phase ratio （O/A） on the extraction rate were investigated. The effects of the concentration of NO3^- and SO4^2- on the extraction rate of Cu, Fe, Zn and Sn were also studied. The results show that the extraction reaches equilibrium quickly, and with increasing equilibrium pH of the aqueous solution, the copper extraction rate greatly increases. The copper extraction rate also increases with increasing concentration of LK-C2 and O/A ratio. The optimum conditions are determined that the concentration of LK-C2 in the organic phase is 15%, the phase ratio （O/A） is 1：1, the pH value of the aqueous solution is 2.00 and the reaction time is 10 rain. The concentrations of NO3^-, SO4^2- and Cl^- have no significant effects on the extraction rate of Cu, Fe, Zn and Sn. Under the optimized operating conditions, copper can be extracted effectively and the extraction rate reaches 99.78% at one stage. Using sulfuric acid solution （2.00 mol/L） as stripping agent, the stripping rate of copper reaches 97.51% after three series of countercurrent extracting.