Formation of Titanium Carbonitride via Carbothermic Reduction of Ilmenite Concentrate in Nitrogen Atmosphere

The carbothermic reduction of ilmenite concentrate with graphite powder was investigated by isothermal experiments under nitrogen atmosphere. The reaction temperatures of the reduction-nitridation process were over a range of 1 473 K to 1 773 K. After various reaction time, the reduction-nitridation products obtained at various temperatures were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). Mass loss was also measured and used to judge the mechanism. The reaction rate and extent of the reduction-nitridation process increased with increasing the reaction temperature. The reaction sequence of the ilmenite concentrate from 1 473 K to 1 773 K in nitrogen was found: FeTiO3 -> Fe + Ti3O5, and Ti3O5 -> TiC1-xOx -> TiC1-xNx. The lowest temperature for the generation of TiC1-xOx and TiC1-xNx was 1 573 K. The incorporation of the nitrogen was found to occur after the formation of TiC1-xNx. Ti2O3 did not appear as an intermediate phase due to its instability in nitrogen atmosphere.