Abstract: Tao Hongbiao，Cao Xuefeng，Lu Jian'an，Zhang Qingpeng，Bai Ding School of Resources Processing and Bioengineering, Central South University Magnetic concentrate from an iron dressing plant in Hebei has good monomer dissociation with fine granularity, but contains high content of silica, which is difficult to remove through low or high intensity magnetic separation. The magnetic iron concentrate on site was treated by reverse flotation for iron increase and impurities reducing. The results showed that with starch+sodium humate (mass ratio of 2∶1) as combining depressant for iron ores, OXP+C-1 (mass ratio of 5∶1) as combining collector for gangues, iron concentrate with Fe grade of 65.17% and Fe recovery of 88.14% was gained by adopting the process of one roughing, one scavenging, two cleanings, middles back to the flowsheet.

Key words: Magnetic separation iron concentrate, Starch+sodium humate, OXP+C-1, Iron increase and silicon reducing