Abstract: A gold mine in Yunnan province produces gold by the traditional cyanidation process.In order to make the cyanide-bearing wastewater reached the discharge standards,the joint process of “two-stage oxidation of sodium hypochlorite + activated carbon adsorption” was carried out to remove cyanide.The results showed under the conditions of m(NaClO)∶m(CN-)=2.5,pH=10.5 in the first stage,and with m(NaClO)∶m(CN-)=7,pH=9.1 in the second stage for reaction time 15 min respectively,the content of cyanide in the liquid waste was declined to 0.19 mg/L from the primary 45.01 mg/L by twice oxidation of sodium hypochlorite.Then,the treated liquid waste was optimized by the activated carbon adsorption process for 1h,and the content of cyanide was declined to less than 0.05 mg/L,which meets the requirement of “Standards for Drinking Water Quality” and “Hygienic Standards of Industrial Enterprises Design”.

Key words: Cyanide-bearing liquid waste, Oxidation of sodium hypochlorite, Activated carbon adsorption, Content of cyanide