Abstract: In order to solve the technical problem of high pH value of tailings drainage in Mirador Copper Mine，based on the study of process mineralogy，ML-1 and lime were used as combined inhibitors for copper and sulfur separation. The results show that under the conditions of pH=11.0，when the dosage of ML-1 is 200 g/t，the separation of copper and sulfur is realized.The copper concentrate obtained in the closed-circuit test contains 26.52% copper and the copper recovery rate is 89.01%.The closed-circuit test results provide a technical basis for the separation of copper and sulfur with low alkalinity in Mirador Copper Mine.

Key words: copper sulfide ore, copper and sulfur separation, low alkalinity, inhibitor