Role of Carbonaceous Reductants in Methanol-Iodination-Assisted Ilmenite Reduction: Kinetic and Reduction Mechanism

Conventional titanium extraction techniques, such as carbochlorination, present significant environmental and safety risks due to the hazardous nature of the chemical reactions involved. This study investigates a more sustainable method for titanium recovery from ilmenite ore by employing carbonaceous reductants, graphite, and palm char under methanol-iodine-assisted reduction conditions. Experiments were conducted in a vertical tube furnace under an argon atmosphere at temperatures ranging from 900°C to 1000°C. The reduction process was facilitated by the simultaneous decomposition of methanol and iodination reactions. Characterization of the reduced products was performed using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), and thermodynamic modeling via HSC Chemistry software. Gas evolution analysis was also conducted to evaluate reaction kinetics. The results demonstrated successful reduction of ilmenite to various titanium oxides (TiO2, TiO, Ti2O3, Ti3O5) and metallic iron. Palm char exhibited superior performance, achieving a titanium yield of 54.0 mass% and a reaction rate constant of 0.0223 mol/cm2·s at 1000°C, compared to 37.4 mass% Ti for graphite. Thermodynamic analysis confirmed the process feasibility, with increasingly negative Gibbs free energy values at higher temperatures. These findings position palm char as a promising, eco-friendly alternative for titanium extraction from ilmenite.