Comminuted by High-pressure Grinding Roller

High intensity pre-concentration of hematite ore comminuted by high-pressure grinding roller (HPGR) was studied by dry magnetic separation and wet magnetic separation，and then the classifying pre-concentration test was done. The results showed that as the roll speed was reduced, the tailings grade and the tailings yield were reduced, while the Fe recovery were raised in dry pre-concentration. As the rod gap was decreased, the rod diameter and the BMFI were increased, the tailings grade and the tailings yield were reduced, while the Fe recovery was raised in wet pre-concentration. The pre-concentration performances were not satisfactory by the single separating method. But when the products in HPGR were screened firstly, and then the oversize products were separated by the dry magnetic separator and the undersize products were separated by the wet high-gradient magnetic separator, the optimum performance for the classifying pre-concentration was obtained at the classifying size of 0.5mm. After classifying pre-concentration, the overall concentrate grade was improved by 8.44%with a recovery of 86.51% and a tailing yield of 35.71% under the condition of the beneficiation feed grade as 24%.