Abstract: There is high content of easy floating calcium-magnesium minerals in a low grade copper mineral，which is apt to be slimed in the grinding process and covered on the chalcopyrite or other mineral's surface，and influences the flotation behavior of copper.In order to realize high efficient concentration of the ore，a mud-mineral separation process on the ore was carried out.The results show that after desliming flotation at the grinding fineness of 52% -74 μm，copper concentrate with copper grade of 18.13% and recovery of 80.86% is obtained through the process of one-roughing，three-cleaning，three-scavenging process and middles back to the flow-sheet in turn for dealing with the slime，and one-roughing，three-cleaning，two-scavenging process and middles back to the flow-sheet in turn for dealing with the products from the flotation cell after regrinding to be 75% -74 μm.With good flotation indicators，this closed-circuit process can be as a reasonable process for concentration of the ore.

Key words: Chalcopyrite, Calcium-magnesium minerals, Easy floating and easy to slime, Desliming, Regrinding, Flotation