Abstract: Through analysis on the ore properties of the extremely refractory surrounding iron ore in JISCO, there are many iron mineral species but low grade. And its main reasons for difficulty to concentrate are higher degree of oxidation and fine particle size of the iron minerals. Experimental researches are carried out by three flow-sheets of stage grinding-single high intensity magnetic separation, stage grinding-high intensity magnetic separation-cationic reverse flotation, stage grinding-high intensity magnetic separation-gravity separation-cationic reverse flotation. The optimal process of stage grinding-high intensity magnetic separation-reverse flotation is determined. Then the optimal process was applied into the pilot verification tests, and the optimum concentration results were achieved ultimately.

Key words: Extremely refractory iron ore, Fine dissemination, High intensity magnetic separation-reverse flotation