Abstract: A mixed copper ore in Yunnan owns a high oxidation rate of up to 47.06%, and the copper minerals are embedded in super fine grain size, and closely associated with gangue minerals, which resulting in difficulty to be classified and separated. The technical conditions for flotation of the ore are explored. The results show that with the activation of sodium sulfide, copper concentrate with Cu grade of 23.03% and Cu recovery of 54.65% was gained by adopting the closed-circuit process of grinding-three roughings-regrinding of rough concentrate-two cleanings.

Key words: Mixed copper ore, High oxidation rate, Activation of sodium sulfide, Re-grinding