Abstract
Iron is the second most important commodity after oil, forming the backbone of global infrastructure and fueling a trillion-dollar metal market. Since 2000, iron production has surged to meet the growing demand for steel in the construction and automotive sectors. As high-grade ore reserves are depleted, there's a shift towards exploiting low-grade iron from secondary sources. This research focuses on using magnetization roasting and induced dry roll magnetic separation to process low-grade iron plant tailings.
The iron plant tailings were characterized using wire mesh sieves for particle size distribution, X-Ray Fluorescence (XRF) for chemical composition, X-Ray Diffractometer (XRD) for mineral phase identification, Scanning Electron Microscopy (SEM) for morphology, and Mössbauer for Fe nuclei phases.
The beneficiation techniques employed in the current study include upgrade using mineral deportment, rougher induced dry roll magnetic separation, magnetization roasting (using two different reductants: coal and macadamia nutshells), and induced dry roll magnetic separation.
The –1180 μm fraction with a total Fe grade of 60.92% at a recovery of 74.10% was obtained based on mineral deportment beneficiation stage. The induced dry roll magnetic separation rougher stage only produced a concentrate with an iron grade of 62.25% at an iron recovery of 81.20% which does not meet the market requirement for iron and steel making.
The grade of iron produced under optimum conditions, roasting temperature of 900℃ and roasting time of 60 minutes, for both reductants during magnetization roasting was at least 65%. However, the macadamia nutshells-roasted iron plant tailings sample recovered 70.9% iron compared to 43.5% for the coal-roasted iron plant tailings sample. The mineralogy of the sample obtained during magnetization roasting revealed the presence of ferrimagnetic phase (magnetite - Fe3O4) which has contributed positive for a selective magnetic separation of iron from impurities.