Abstract: 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.

Key words: electrodeposition, copper-cyanide wastewater, copper and cyanide recovery, gold mine, thermodynamics