A novel approach of utilizing the waste biomass in the magnetizing roasting for recovery of iron from goethitic iron ore

The present study investigates the recovery potential and degree of grade-upgradation for goethitic iron ore upon treatment with magnetizing roasting. Magnetizing roasting has gained interest among its peers due to its low floor/water footprint, ease of techno-economics, zero process limitations, a higher degree of grade/recovery, etc., compared with existing ore dressing methods. Magnetizing roasting comprises roasting followed by magnetic separation. In the previous studies, process is stabilized for parameters such as roasting temperature between 700 to 1000 °C, roasting time between 10 to 50 min, and in presence of 30 wt.% of coal, followed by magnetic separation with magnetic strength ranging between 1000 to 3000 Gauss. Best set of optimal recovery and iron ore grade acquired are 87.44% and 72.46% with operating conditions at (a) roasting temperature — 850 °C, (b) roasting time — 30 min, and (d) magnetic strength — 3000 Gauss. Furthermore, as environmental protection agencies are necking down and gripping the utilization of coal/coke and imposing a carbon tax, integration of carbon-neutral fuel sources like biomass and biochar has become mandatory. In accordance with this, a comparative scheme employing a variety of biomass/biochar as coke substitutes in a progressive blending mode was used to investigate the possibility of substitution. The goal is to maintain the same level of upgradation and recovery potential throughout this process. The four types of biomass/biochar used for magnetizing roasting; with rice husk char (RHC), this partial substitution campaign concluded a recovery potential of 78–80% and a goethite ore grade of 72%. •At 850 °C, goethite in low-grade iron ore can be successfully converted to magnetite by biomass.•Four biomass/biochar used as a renewable solid reductant in magnetization roasting.•The result is iron concentrates with a grade of 72.93% and a recovery of 77.34%.•Porosity develops in the mineral as a result of reduction and dehydration. [Display omitted]