Characterization and Upgrading of Low-grade Brahmaputra River Basin Ilmenite Concentrate: Exploring an Alternate Feedstock for Synthetic Rutile Preparation

This research focuses on characterizing river basin ilmenite and upgrading it to synthetic rutile through direct hydrochloric acid leaching. The ilmenite was fractionated from heavy mineral concentrates by physical separation, which were collected from the transboundary Brahmaputra River basin sandbars in Bangladesh. The ilmenite and prepared titanium products were characterized by wavelength dispersive x-ray fluorescence, grain size analysis, x-ray diffraction, optical and scanning electron microscopy, and Raman spectroscopy. The river basin ilmenite concentrate is low grade and contains 27.02% TiO2 and 60.62% Fe2O3t, composed of ilmenite, hemo-ilmenite, ilmeno-hematite, and some locked grains of gangue minerals. The titanium product prepared from river basin ilmenite by direct hydrometallurgical processing showed 95.61% TiO2, 3.81% Fe2O3t, and 0.58% other oxides, and corresponds to a complete rutile phase. This synthetic rutile also exhibited a porous structure, crushed crystallites, and a particle size of < 0.5 mu m. Except for the Fe2O3t content, which might be reduced by chlorination, all the attributes of the synthetic rutile meet the requirements for industrial use. This could make river basin ilmenite a viable alternative to conventional ilmenite feedstock from beach placers or massive crystalline ores.