Abstract: A gold ore in Central Asia contains 0.21% copper and 6.32 g/t gold. Primary copper sul⁃ fide and secondary copper sulfide account for 96.22% of the total copper. The exposed gold and sulfide en⁃ crusted gold accounted for 90.07% of the total gold，and the sulfide encrusted gold was mainly chalcopy⁃ rite. In the field，copper-sulfur mixed flotation using one roughing，one cleaning and one scavenging，and copper-sulfur separation using two roughing and three cleaning when the mixed concentrate was ground to - 38 μm accounting for 90% was carried out，while the grade of gold and copper concentrate was only 4.72%. In order to obtain gold and copper concentrate with copper grade over 20%，the separation reagent of copper and sulfur of mixed concentrate was optimized. The results showed that gold and copper concen⁃ trate with copper grade of 22.39%，gold grade of 602.61 g/t，copper recovery of 85.34%，gold operation re⁃ covery rate of 63.68%，and sulfur gold concentrate with gold grade of 13.28 g/t and gold operation recovery rate of 36.32% were obtained by the process of separation of copper and sulfur with two roughing and three cleaning and middling return in sequence with collectors of Z-200 and lsoamyl xanthate. Compared with the on-site production concentrate，the gold grade of gold and copper concentrate increased from 139.50 g/ t to 602.61 g/t，the copper grade increased from 4.72% to 22.39%，and the Cu recovery rate increased by 9.35 percentage points. In the closed circuit test，the gold leaching rate of sulfur-gold concentrate was 69.49%，the gold grade of leaching residue was 4.08 g/t，and the final comprehensive recovery rate of gold was 88.92%，which reached the ideal experimental effect.

Key words: gold-copper ores, mixed floatation, regrinding, copper-sulfur separation flotation, re? agents system optimization