Abstract: There is 1.06% Cu, 0.38 g/t Au, 3.56% S in a gold-bearing copper ore in Yunnan. In order to recovery gold during copper recovery process, flotation tests under natural pH conditions were conducted. Results show that, the new environmental protection inhibitor D82 can effectively inhibit the recovery of pyrite while improving the recovery of gold. Under the conditions of grinding fineness of -0.074 mm and 75.5%, using D82 as the inhibitor, Z-200 as collector, after one roughing two cleaning two scavenging copper flotation, copper flotation tailings with copper sulfate as the activator, butyl xanthate as collector, after one roughing one cleaning one scavenging sulfur flotation closed circuit flotation, copper concentrate with copper grade 46.83%, gold grade 14.22 g/t, copper recovery rate 93.22%, gold recovery rate 78.96%, sulfur concentrate with sulfur grade 58.69%, recovery rate 75.18% was obtained. The process of copper flotation sulfur depression using D82 as depressor under natural pH conditions has reference values for sulfide ore flotation, which associated with precious metals.

Key words: Copper sulfide ore, Flotation at natural pH flotation, Depressor D82