Sustainable iron recovery from iron ore tailings using hydrogen-based reduction roasting and magnetic separation: A pilot-scale study

Abstract

Iron tailings are a common solid waste resource, posing serious environmental and spatial challenges. This study proposed a novel hydrogen-based reduction roasting (HRR) technology for the processing of iron tailings using a combined beneficiation and metallurgy approach. Pilot-cale experiment results indicated that under the gas composition of CO:H₂ = 1:3, and optimal roasting conditions at a reduction temperature of 520 °C, the majority of weakly magnetic hematite transforms into strongly magnetic magnetite during the reduction process. Combining roasting products with a magnetic separation–grinding–magnetic selection process yields a final iron concentrate with a grade of 56.68% iron and a recovery rate of 86.54%. Theoretical calculations suggested the annual production value can reach 29.7 million USD and a reduction of 20.79 tons of CO₂ emissions per year. This highlights that the use of HRR in conjunction with traditional beneficiation processes can effectively achieve comprehensive utilization of iron tailings, thereby reducing environmental impact.