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

Abstract

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 1473 K to 1773 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 1473 K to 1773 K in nitrogen was found: FeTiO₃ → Fe + Ti₃O₅, and Ti₃O₅ → TiC_1-xO_x → TiC_1-xN_x. The lowest temperature for the generation of TiC_1-xO_x and TiC_1-xN_x was 1573 K. The incorporation of the nitrogen was found to occur after the formation of TiC_1-xO_x. Ti₂O₃ did not appear as an intermediate phase due to its instability in nitrogen atmosphere.