Abstract:

In the system of gold concentrate roasting-cyanide，the closed-circuit of barren solution containing cyanide need to  be opened periodically，the copper in which has some recovery value.The feasibility of recovering copper from barren solution containing cyanide is investigated on the basis of acidification process.After the acidification the evaporation rate of cyanide ion is 95.42% and the precipitation rate of copper is 97.82%.There is 22.77%～35.01% of copper in the acid sedimentation separated from acidified barren liquid.The copper can be reclaimed by a roasting-acid leaching-extraction technique，and the best experiment conditions are as follows：roasting temperature is 640 ℃，Liquid-solid ratio is 5∶1，the concentration of H2SO4 is 5%，acid leaching time is 3 hours，and the copper leaching rate is up to 92.27%～95.00%.If 20% Lix984 is used as extraction agent，pH value of leaching solution is 2.3，organic and aqueous phase ratio（O/A） is 1∶1，one stage copper extraction rate is 98.96% after 3~5 min extraction.The copper concentration in the solution separated from acidified barren liquid is 72.89 mg/L，sulfurized method is used in the copper deposit，if Na2S is 0.4～0.6 g/L，the copper sedimentation rate is up to 92.21%～99.09% after one hour.

Key words: roasting cyanide, barren solution containing cyanide, copper, acidification method, sedimentation, roasting-acid leaching-extraction, sodium sulfide