A clean and green technology for iron extraction from refractory siderite ore via fluidization self-magnetization roasting

Abstract

As a refractory iron resource, siderite has gained significant attention in the fields of mineral processing and metallurgical industry due to its abundant availability. However, its direct utilization in iron and steel production is often hindered by the presence of impurities, including silicates and carbonates, as well as the lower theoretical iron grade so it is necessary to increase iron and reduce impurities. To unlock the full potential of these abundant iron ore deposits, advanced processing techniques are imperative. In this work, a clean and green technology was proposed for extracting iron from siderite via fluidization self-magnetization roasting and magnetic separation. The mechanism of fluidization self-magnetization was investigated by thermodynamic analysis, X-ray diffraction (XRD), iron phase analysis, Mineral Liberation Analyzer (MLA), vibrating sample magnetometer (VSM), scanning electron microscope (SEM) combined with energy dispersive spectroscopy (EDS). The results show that concentrate with a Fe grade of 61.74% and Fe recovery of 81.78% could be obtained after treatment by fluidization self-magnetization roasting and magnetic separation. The analysis reveals the siderite eventually transformed into magnetite after fluidization self-magnetization roasting, with the saturation magnetization increasing from 0.91 A·m2·kg−1 to 7.92 A·m2·kg−1. In this process, many cracks were generated on the surface of the ore, which not only likely contributes to the self-magnetization roasting but also facilitates the individual dissociation of iron minerals from gangue minerals during the grinding process. Subsequently, iron minerals can be recovered through magnetic separation. The fluidization self-magnetization roasting technology demonstrates significant potential in achieving the green and clean utilization of siderite.