Experimental study of direct reduction-magnetic separation of JISCO compound dust ash

The treatment of dust removal ash has always been a serious problem in the metallurgical field. To realize the resource utilization of dust removal ash and reduce the impact of its harmful elements on the surrounding ecological environment, six kinds of dust removal ash from JISCO were compounded and designed to verify the feasibility and efficiency of removing harmful elements from them by the pyrometallurgical process. According to the results of the direct reduction experiments, suitable experimental ingredients were determined for the kiln slag magnetic separation. The experimental results showed that the burn loss rate was 36.62% after roasting under the conditions of the mass percentage compounding of BFBD (Blast Furnace Bag Dust)∶ SSDA (Secondary Steelmaking Dust Ash)∶ SBFBA (Stored Blast Furnace Bag Ash)∶ MDA (Mixed Dust Ash)∶ BFGDA (Blast Furnace Gravity Dust Ash)∶ OG (Oxygen Gas Mud) = 28.50∶7.50∶15.50∶6.50∶28.50∶13.50, with a carbon content of 30%, roasted at 1 100 ℃ for 60 min. The rates of dezincification, depotassication and desodium were 67.86%, 75.56% and 72.41%, respectively. Furthermore, the iron grade in the roasted material was 30.77%, and the iron concentrate powder with 80.84% grade was obtained after fine grinding and magnetic separation, achieving an iron recovery rate of 81.44%. The experimental study and the associated mechanism analysis of metallic iron recovery with direct reduction and magnetic separation after compounding multiple dust removal ash are expected to provide a promising new approach for treating dust removal ash.