电沉积回收氰化尾液中铜和氰化物的研究

采用热力学方法计算了高铜高氰溶液中铜氰络合离子的存在形式,以及溶液中各物质的阴极析出电位和阳极氧化电位.理论分析表明,在本实验条件下,溶液中铜氰络离子主要以Cu(CN)3-4和Cu(CN)2-3的形式存在,且以Cu(CN)3-4的形式为主,温度及pH值对铜氰络合离子的存在形式有明显影响.选用合适的电极材料通过电沉积法对氰化尾液进行处理,结果表明,该方法可以在回收废水中铜的同时有效避免氰化物的分解,铜的电流效率可以达到36%以上,溶液中游离氰根浓度由0.096 mol/L提高到0.316 mol/L.实验证明了采用电沉积法处理高铜高氰氰化尾液的可行性.

Study on Electrodeposition Recovery of Copper and Cyanide from Cyanide-Containing Wastewater

The forms of copper cyanide species and the data of deposition and oxidation potentials in high-copper and high-cyanide wastewater were determined by thermodynamic calculation and laboratory experiments. The results confirm that copper cyanide species exist mainly as Cu(CN)^3-₄ and Cu(CN)^2-₃， where the former is dominant. The form of copper cyanide is significantly affected by temperature and pH. With suitable electrode materials， copper could be recovered and the decomposition of cyanide could be prevented effectively in the electrodeposition process. The maximum current efficiency exceeded 36%， and the concentration of free cyanide increased from 0.096mol/L to 0.316mol/L. The feasibility of treating high-copper and high-cyanide wastewater by electrodeposition is proved by the present experiments.