Experimental Studies On Iron Recovery Of Iron-containing Dust Slime

At present, self-sufficiency rate of iron ore required by China's steel industry is about 46%. In order to resolve a serious shortage of domestic iron ore resources, it is necessary to exploit and utilize secondary iron ore resources. In 2009, Steel production in china reached about 0.565 billion tons, through 8% to 12% of which is iron-bearing dusts (IB dusts). It is a huge waste about iron resources if these dusts can't be utilized properly. Most of the IB dusts, such as blast furnace dust, blast furnace sludge and converter dust, are currently utilized in metallurgy enterprises through return to sintering. Because these dusts are extremely small in size and contains harmful impurties, they have a negative impact on sintering and blast furnace process. It is necessary to develop a new method or routine to exploit the IB dusts.In this article, three types of separation processes have been proposed and compared to recover iron concentrate from the IB dusts as follows: low intensity magnetic separation, high gradient intensity magnetic separation and magnetization roasting-magnetic separation. Studies on process mineralogy showed, TFe was 31% and C content was 33.65% in blast furnace dust; TFe was 42.4% and C content was 16.15% in blast furnace sludge; TFe was 54.8% in converter dust; and iron oxides was mainly Fe₂O₃ in all three dusts.Using low intensity magnetic separation, we got the best magnetic indicator: iron concentrate grade of blast furnace dust was 55% and iron recovery rate was 60%; iron concentrate grade of blast furnace sludge was 61% and iron recovery rate was 31%; iron concentrate grade of converter dust was 61% and iron recovery rate was 16%. Moreover, using high gradient intensity magnetic separatio, we got the best magnetic indicator: iron concentrate grade of blast furnace dust was 53% and iron recovery rate was 75%; iron concentrate grade of blast furnace sludge was 51% and iron recovery rate was 42%; iron concentrate grade of converter dust was 57% and iron recovery rate was 72%. Lastly, using magnetization roasting-low intensity magnetic separation, we got the best magnetic indicator: mixture iron concentrate grade of blast furnace dust and converter dust which mass ratio was 6%.Iron concentrate grade was 61% and iron recovery rate was 86%; iron concentrate grade of blast furnace sludge was 61% and iron recovery rate was 89%.