Pilot-scale Study on Direct Reduction of High Phosphorus Oolitic Hematite by Rotary Hearth Furnace

With a pilot-scale test, high phosphorus oolitic hematite was firstly carried out in a rotary hearth furnace by direct reduction roasting and magnetic separation. Under the conditions of the mixed material mass ratio of raw ores, reduction coal, limestone and dephosphorization agent at the ratio of 100 GA6FA 20 GA6FA 15 GA6FA 1, the rotary hearth furnace roasting temperature from 1 150℃ to 1 250℃, the reduction time of 70 minutes, the thickness of containing coal pellets from 2 to 3 layers (55 to 65 mm), the metallized pellets could be obtained with an average metallization rate of 88.97%, the yield of iron powder treated with two stages grinding-magnetic separation of 42.35%, the TFe grade of 92.56%, the iron recovery of 84.26% and the P grade of 0.04%. The metal iron powder with a compact density of 5.02 t/m³ could be used as the high-quality steelmaking material in the electric furnace. The metal iron powder obtained by grinding separation of the metallized pellets with the roasting temperature of 1 250℃ and 1 300℃were analyzed by the scanning electron microscope (SEM). The result showed that phosphorus could be found in the metal iron powder with the roasting temperature of 1 300℃. It illustrates that the reduction temperature should be regulated to restore the iron selectively, rather than phosphorus with the high phosphorus oolitic hematite.