Mineralogy of Magnetite Concentrate and Its Preparation for Ultra-pure Iron Concentrate

A comprehensive investigation was undertaken on the mineralogy of ordinary magnetite concentrate to achieve ultra-pure iron concentrate. Various analytical methods, including chemical analysis, X-ray fluorescence spectroscopy, optical microscopy, scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM-EDS), and mineral liberation analysis were employed. The analysis revealed that the ordinary magnetic concentrate had a TFe grade of 65.56%, accompanied by Al₂O₃ and SiO₂ contents of 0.38% and 8.28%, respectively. The valuable mineral identified in the sample was magnetite, constituting 89.01%, exhibiting a liberation degree of 90.66%. The predominant gangue minerals, quartz and amphibole, exhibited low liberation degrees of 24.11% and 20.94%, respectively. Subsequently, a combined beneficiation process involving shaking table separation and reverse flotation was conducted. Experimental results demonstrated that ultra-pure concentrate with a TFe grade of 72.20% and recovery of 51.54% was obtained through one stage of shaking table separation, roughing flotation, and four cleaning flotation stages. The ultra-pure magnetite was further confirmed by XRD analysis, magnetic susceptibility measurement, and SEM-EDS analysis. The successful implementation of this process will provide a benchmark for producing similar ultra-pure magnetite concentrates.