A Novel Self-Magnetizing Roasting Process for Recovering Fe from Low-Grade Pyrite Cinder and Blast Furnace Sludge

Abstract

A novel self-magnetizing roasting process was developed to recover Fe from low-grade pyrite cinder and blast furnace sludge. Blast furnace sludge is a weaker reductant than conventional reductants but can be used as a reductant in magnetizing roasting reactions. The optimal magnetizing roasting–magnetic separation process conditions were 40% blast furnace sludge: 60% pyrite cinder (by weight), roasting temperature 750 °C, roasting time 30 min, magnetic field intensity 0.2 T, and grinding fineness − 0.074 mm 91.35%. The iron concentrate produced was of grade 59.23%, the recovery was 71.65%, and acceptable hazardous elements (Pb, S, and Zn) were present. The iron concentrate will therefore act as a suitable sintering or pelletizing feedstock. The results indicate that blast furnace sludge is a suitable reductant for self-magnetizing roasting pyrite cinder. Developing the method will allow these solid wastes to be used in economically and environmentally beneficial ways.