Pilot Study on Direct Reduction of Low Grade Refractory Iron Ore by Rotary Hearth Furnace

The pilot scale test of the low grade refractory iron ore was carried out in a rotary hearth furnace by direct reduction roasting and magnetic separation. The metallized pellets with a average metallization rate of 83.44% could be obtained by the mixed material ratio of raw ores, coke powder, bentonite and liquid binder at the ratio of 100:33:4:8, rotary hearth furnace roasting temperature from 1 250 ℃ to 1 330 ℃, reduction time of 42 minutes, and the thickness of carbon-containing pellets of 3 layers (about 60 mm). After the two stages of grinding-magnetic separation, the reduction iron powder could be obtained with yield of 39.52%, TFe grade of 94.39% and iron recovery of 83.34%. The reduction iron powder could be compressed into blocks with the density of 4.78 t/m³, which could be used as a high-quality charge for electric steelmaking.