The converter slag from a smeltery in Daye contains 2.01% copper.The floatability of copper has a significant influence on the flotation of converter slag.Flotation tests,contact angle tests and FTIR were conducted to assess the influences of pH and different flotation concentrators on its hydrophobic process,mechanism and flotation.The results show that since chemisorptions are formed on the surface,hydrophobicity of copper is highly enhanced by xanthate,butylamine dithiophosphate and Z-200.The hydrophobic-surface of copper becomes worse with low recovery in strong acid and alkali situation.When pH value is 10,butylamine dithiophosphate and butyl xanthate are used as the mixed-collector,the grade of copper is 40.01%and that of tailings is 0.37%. The converter slag from a smeltery in Daye contains 2.01% copper. The floatability of copper has a significant influence on the flotation of converter slag. Flotation tests, contact angle tests and FTIR were conducted to assess the influences of pH and different flotation concentrators on its hydrophobic process, mechanism and flotation. the results show that since chemisorptions are formed on the surface, hydrophobicity of copper is highly enhanced by xanthate, butylamine dithiophosphate and Z-200. hydrophobic-surface of copper becomes worse with low recovery in strong acid and alkali situation. The pH value is 10, butylamine dithiophosphate and butyl xanthate are used as the mixed-collector, the grade of copper is 40.01% and that of tailings is 0.37%.