In view of the low grade of mixed copper-molybdenum concentrates produced by the concentrator of Duobaoshan Copper Mine and the high mass fraction of silicon and aluminum,the main reason for the low grade of copper concentrate is analyzed and it is considered that the copper and molybdenum minerals are embedded in fine grains and have poor monomer disintegration degree,and closely related to gangue minerals.In view of the significant advantages of the Isa mill in the field of ultra-fine grinding,the mill is creatively applied to the copper coarse concentrate regrinding process.The results show that the product has the grain size of 80 %-28 μm.The grinding power consumption is 23-24 kW·h/t,and the grinding efficiency is high.4 times of cleaning after regrinding obtains mixed copper-molybdenum concentrate where copper grade is 25.870 % and molybdenum grade is 0.770 %.The recovery rate of ore dressing assured,it effectively improves the quality of mixed copper-molybdenum concentrate,reduces the mass fraction of silicon and aluminum,increases the economic value added of the product,and also creates the favorable conditions for subsequent copper-molybdenum separation.