关键词: 金矿, 浮选, 中矿再磨

Abstract: The grade of a gold ore from Luoyang is 4.15 g/t.Gold is fine disseminated in the ore，and mainly in pyrite inclusions，it's difficult to be exposed for dissociation.This characteristic greatly affects the gold recovery.To provide basis for the development and utilization of the ore，beneficiation study was conducted.Under the grinding fineness of 66% -0.074 mm，via closed-circuit flotation process of one roughing-two cleaning-two scavenging，middling back to the flowsheet in turn，gold concentrate with gold grade of 52.25 g/t and recovery of 85.90% was obtained，and the tailings contained 0.625 g/t gold.Mineralogy analysis of intermediate product showed that there were many particles of undissociated pyrite in concentrate of scavenging 1.Thus，another closed-circuit test was carried out adding regrinding on the concentrate of scavenging 1 to 68% -0.043 mm.The grade of the gold concentrate was 57.40 g/t，with the recovery of 90.88%，and the grade of the tailings was reduced to 0.4 g/t.The flotation result was significantly improved than original flotation test.Middling regrinding is a critical technique for beneficiation index improve of the ore.

Key words: Gold ore, Flotation, Middling regrinding