Abstract:Cyanide tailing slurry was detoxicated by Na2S2O5-Air method. The results show that cyanide concentration in tailing slurry drops from 165 mg/L to 0.105 mg/L, copper content drops from 7.95 mg/L to 0.51 mg/L, and contents of COD、Pb、Zn、As、SCN- can reach the second level discharging standard of GB8978-1996 under the conditions including pH value of 10.2, Na2S2O5 dosage of 4.0g/L, no addition of copper sulfate, no air inflation, and stirring time of 2.5h. The treated tailings can be directly discharged as their leaching toxicity can reach the standard of GB5085.3-2007.