Abstract: The recovery rate of copper-nickel mixed concentrate in a low-grade copper and nickel ore on-site of Hunan is low On the basis of process mineralogical study and field test results，the paper focuses on researches the ore grinding fineness， reagent system and optimization of the flow-sheet processUnder less changing of on-site process and reagent regime， copper-nickel mixed concentrate with Cu grade and recovery of 465% and 8648%， Ni grade and recovery of 364% and 7506% were obtained In comparison with the field production index， copper recovery rate is increased by 311 percentage point，nickel recovery rate is increased by 461 percentage point with the concentrate quality improved slightly.

Key words: Copper-nickel ores, Beneficiation index, Regulator F-8, Ammonium butyl aerofloat+D20+A12