Abstract:The first stage grinding system of 6500t / D Copper-sulphur concentrator of Yinshan mining adopts SABC process, and eight FX660 hydrocyclones are used for grinding and classification, the bench efficiency of the grinding system was increased from 270.8 T / h to 300 t / h at the beginning of operation. The content of-74 Micron grade in the overflow of the cyclone reached over 65% ,but the content of + 178 Micron grade reached 9.36, which was slightly higher than the requirement of the plan. In order to reduce the + 178 Micron level content in the overflow of the cyclone, the optimized upgrade of the cyclone FX60 was carried out by adopting a new structure cyclone with a spiral case pre-graded feed body and adjusting the diameter of the overflow pipe and the grit-sinking nozzle of the cyclone, the + 178 Micron content in the overflow of hydrocyclone was reduced by 3.02 percentage points, the-74 Micron level was increased by 1.85 percentage points, and the classification efficiency of hydrocyclone was increased by 1.77 percentage points. The sand return ratio of the classification operation was reduced by 29.23 percentage points.