高磷鲕状赤铁矿转底炉直接还原中试研究

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

首次采用转底炉直接还原焙烧—磁选方法,对高磷鲕状赤铁矿进行了转底炉中试试验研究。在混合物料配比为m(原矿)GA6FAm(还原煤)GA6FAm(石灰石)GA6FAm(脱磷剂)=100GA6FA20GA6FA15GA6FA1,转底炉焙烧温度1150℃~1250℃,还原时间为70 min,含碳球团厚度2~3层(约55~65 mm)的条件下,最终获得的球团平均金属化率88.97%,两段磨矿磁选所得金属铁粉产率42.35%,TFe品位92.56%,铁回收率84.26%,P含量0.04%。金属铁粉压块密度为5.02 t/m3,可以作为优质的电炉炼钢原料。用扫描电镜(SEM)对焙烧温度1250℃和1300℃的金属化球团磨选所得金属铁粉进行分析,焙烧温度1300℃的球团磨选金属铁粉中有单质磷的存在,说明对高磷鲕状赤铁矿而言,必须控制还原温度,选择性还原铁,避免还原磷。

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 1150℃to 1250℃,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 1250℃and 1300℃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 1300℃.It illustrates that the reduction temperature should be regulated to restore the iron selectively,rather than phosphorus with the high phosphorus oolitic hematite.