The cyanide tailings washing water containing a high concentration of ferricyanide complex and copper cyanide complex in a gold smelting enterprise was used as the treatment object to purify the cyanide in washing water by the processes of copper precipitation by acidification-cyanide precipitation from ferrous salt-neutralization and copper precipitation by sulfuration-cyanide precipitation from ferrous salt-neutralization.The optimal test parameters were investigated and the 2 processes were compared.Under the optimal conditions,the total cyanide mass concentration in the washing water was less than 50 mg/L,the copper mass concentration was less than 20 mg/L,and iron mass concentration was less than 50 mg/L,meeting the requirements of the process reuse standards.The 2 processes both can achieve effective separation of ferricyanide complex and copper cyanide complex,recovering valuable metal copper while deeply removing cyanide from wastewater.However,the reaction conditions should be strictly controlled in the process and the reaction equipment and management are demanding.