High-Flux Radiation-Driven Beneficiation of Low-Grade Iron Ore: Impact on Separation Performance and Grinding Energy Requirements

Abstract This study presents a detailed experimental investigation into the thermally assisted beneficiation of a low-grade, goethite-rich iron ore (54.1 wt pct Fe, -4.75+4 mm particle size) using a novel high-flux radiation technique. This method features a high heating rate and relatively short residence time compared to conventional approaches, and is subsequently followed by grinding and magnetic separation. The overall beneficiation performance was assessed in terms of particle grindability, iron upgrade and recovery, and impurity removal, and was supported by mineralogical and micro-structural analyses. Mild heat treatment at 500 °C, combined with grinding and wet high-intensity magnetic separation at 1 Tesla, effectively upgraded the ore, yielding a hematite-rich concentrate with up to 61 wt pct Fe and a recovery of up to 83 pct Fe. This product is suitable for both traditional and emerging green steelmaking pathways. Heat treatment also enhanced ore grindability through thermally induced cracking, leading to an estimated reduction of up to 31 pct in grinding energy requirements. The specific surface area of the ore increased by more than fivefold after heat treatment at 500 °C, producing a material with higher surface area and potentially enhanced reactivity which may be favorable for downstream processing. The proposed beneficiation strategy enabled up to 70 pct removal of alumina and silica impurities; however, only minimal removal of phosphorous could be achieved, likely attributed to micron-scale interlocking of fluorapatite with iron minerals. Overall, the high-flux radiation technique offers a promising route for thermally assisted beneficiation, with potential for reduced equipment size, lower energy consumption, and decreased heating costs.