Abstract:A pressurized oxidation method was adopted for the decyanidation of cyanide wastewater from gold smelting, and the effects of reaction temperature, oxygen partial pressure, reaction time and acidity on the removal of total cyanide, thiocyanate ion and heavy metal ions from cyanide wastewater degraded by pressurized oxidation were investigated. The results show that increasing the reaction temperature, oxygen partial pressure, reaction time and acidity are all favorable to the removal of total cyanide from cyanide-containing wastewater. When the reaction temperature is 80 ℃, oxygen partial pressure is 0.3 MPa, reaction time is one hour, and the dosage of concentrated sulfuric acid is 0.31 mol/L during acidification, the total cyanide can reduce to 22.2 mg/L and further reduce to 7.73 mg/L after two days of static storage, the SCN- reduces to 13.8 g/L, Cu reduces to 30.3 mg/L, Fe reduces to 3.21 mg/L, and Zn reduces to 2.2 mg/L. Cu, Fe, and Zn are almost all immobilized in the precipitates in the form of Zn3(Fe(CN)6)2, Cu2Fe(CN)6?2H2O and Fe4(Fe(CN)6)3, respectively, which in turn reduces the toxicity of gold smelting wastewater. After pH adjustment, the degraded wastewater can be returned to the gold mine cyanide leaching process to realize the recycling of wastewater.