Applicability of carbothermic reduction for upgrading Sri Lankan ilmenite ores: towards converting ilmenite into synthetic rutile by mechanical activation

Abstract

The milled samples were subsequently heated for two hours continuously at temperatures of 800 °C, 900 °C, 1000 °C, 1100 °C, and 1200 °C, respectively. Initial and annealed samples were analysed using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and X-ray fluorescence (XRF) analyses. XRD pattern of the initial sample was characterized by less percentage of rutile (TiO2) peaks and low crystallinity. However, the number of rutile peaks and crystallinity were increased with respective milling hours and annealed temperature. Besides, XRD analysis indicates a higher number of sharp and intense rutile and elemental iron peaks in the samples annealed above 1000 °C. FTIR analysis of raw ilmenite indicates mainly stretching vibrations of Fe–O. However, vibrational spectral bands around 700 cm−1 in samples annealed above 1000 °C are assigned to Ti–O–Ti stretching vibrations. High TiO2 and TiO2 + Fe2O3 (total) wt. (%) can also be observed in samples annealed above 1000 °C.