Abstract: Waste cupronickel is widely used in many fields, with the increasing demand and consumption of waste cupronickel, a large amount of waste copper alloy has been produced. Although the traditional wet process can remove some insoluble impurities and the working conditions are superior, the process is long and the energy consumption is high. Therefore, this work high-purity copper (Cu) was recovered from waste cupronickel by electrolysis separation at 363 K and 0.1~0.5 V cell voltage in choline chloride-glycol deep eutectic solvent (ChCl-EG DES) with the molar ratio of 1:2 as an electrolyte, waste cupronickel as an anode, and titanium sheet as a cathode. Electrochemical tests exhibited that Cu can be dissolved as monovalent Cu(I) into ChCl-EG DES, and the reduction of Cu(I) at the concentration range of 0.5~2.5 mol/L CuCl was a quasi-reversible process. The calculated Ea of the anode dissolution process was only about 28.361 kJ/mol, indicating that the dissolution process of Cu in ChCl-EG DES was controlled by diffusion. The anode polarization curve implied that Sn was dissolved into the solution first, while the dissolution potential of Ni and Fe was similar to that of Cu, and they were entered into anode slime. The electrolysis experiment showed that when the cell voltage increased, both the DC power consumption and the current efficiency increase accordingly. When the cell voltage was at 0.5 V, the current efficiency of electrochemical recovery of waste cupronickel was as high as 97.20%, and the DC power consumption was 216.94 kWh/t. At higher cell voltage (0.3~0.5 V), the morphology of cathode copper was irregular mass with a particle size of 30~50 μm, and the purity of copper can be obtained at the cathode at 0.4 V cell voltage was as high as 99.95wt%.

Key words: waste cupronickel, electrochemistry, recovery, deep eutectic solvent, high-purity copper

摘要： 以摩尔比为1:2的氯化胆碱-乙二醇低共熔溶剂(ChCl-EG DES)为电解液，废白铜为阳极，钛片为阴极，在363 K和0.1~0.5 V槽电压下对废白铜进行电解分离，在阴极获得了高纯铜(Cu)。电化学测试表明，在ChCl-EG DES中金属铜溶解后以Cu(I)形式存在，0.5~2.5 mol/L CuCl浓度范围内Cu(I)的还原是一个准可逆过程。测试了Cu在低共熔溶剂中的动电位极化曲线，计算得出阳极溶解的表观活化能Ea仅为28.361 kJ/mol，表明Cu在ChCl-EG DES中的溶解过程受扩散控制。研究了杂质金属在溶解过程中的阳极极化曲线，结果表明，Sn最先被溶解进入到溶液中，而Ni和Fe的溶解电位均正于Cu，则以阳极泥的形式进行回收。电解实验发现，当槽电压升高时，直流电耗和电流效率均随之增加。当槽电压为0.5 V时，电化学回收废白铜的电流效率高达97.20%，直流电耗为216.94 kWh/t。在较高槽电压下(0.3~0.5 V)，阴极铜的形貌为粒径30~50 μm的不规则块状，在0.4 V时获得的铜纯度高达99.95wt %。

关键词: 废白铜, 电化学, 回收, 低共熔溶剂, 高纯铜