Magnetization roasting of waste iron ore beneficiation plant tailings using sawdust biomass; A novel approach to produce metallurgical grade pellets

Abstract

Minerals recovery and recycling of valuables from industrial waste using biomass (renewable energy resource) is the need of the hour for mineral-rich countries worldwide. Moreover, growing steel demand and fossil fuel consumption led civilization to ponder the alternative raw materials and energy sources apart from conventional coal/coke as an appropriate reductant for the iron and steelmaking process. Therefore, the generated waste iron ore beneficiation plant tailings (IOBPT) containing 56.96% Fe(T), 4.07% Al2O3, 7.23% SiO2 and 4.38% of LOI (contributed mainly from clay and goethite) can be considered a potential secondary mineral resource consumed in the downstream iron making processes. In the current investigation, a novel approach of magnetization roasting of the IOBPT using sawdust biomass (SDB) (generated from the sawmill) as a carbonaceous solid reductant is used to recover the pellet grade magnetite concentrate. On the other hand, the IOBPT was directly subjected to a wet high-intensity magnetic separator (WHIMS) to compare the generated pellet grade concentrate in both methods. In this regard, the quality of the concentrate and indurated pellets obtained from both processes was characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), wet chemical analysis, and X-ray microtomography (X-ray microCT), respectively. Altogether, the innovative way of utilizing SDB as a suitable reductant in magnetization roasting at 950 degrees C to produce metallurgical grade pellets (CCS:258 kg/pellet, Porosity:25.68%, RI:0.71%/min at Rt = 60, RDI-2:RDI]-2.8 = 2.61%, FSI:19.05%) indicates towards a fossil fuel free industrialization.