In-situ processing and characterization of Fe–TiCN composite produced via enhanced carbonitrothermic reduction of low grade ilmenite concentrate

The present study reports the in-situ synthesis of Fe–TiCN composite via carbonitrothermic reduction of ilmenite concentrate. The fraction of ilmenite reacted and the synthesized phases thereof were discussed. The mechanism of titanium carbonitride phase formation from ilmenite was established on the basis of its phase stability in the FeTiO₃ – Carbon system at 800–1400 °C, using FactSage 7.0™ Database and Simultaneous thermal analyser (STA 449 F1 TGA-DTG). The as – reduced products (synthesized Fe–TiCN powders) were characterized using field emission scanning electron microscopy (FESEM) to study the particle morphology and evolving microstructure, and X-ray diffraction spectrometer (XRD) was used to analyze the possible phase transformations during the reduction process. To further confirm that the synthesized powder was pure Fe–TiCN, high resolution transmission electron microscope (HRTEM) was used to study its lattice orientation and particle distribution. Mass loss was measured and used to calculate the percentage/extent of reduction during the carbonitrothermic reduction. The reaction sequence of the ilmenite transformation from 800 °C to 1400 °C was found to be: FeTiO₃ – ‘Fe + TiO₂’ – Ti₃O₅ – TiCN, and Ti₂O₃ was not observed throughout the reduction. An optimal amount of 97.95% extent of reduction was recorded, as the FeTiO₃ completely transformed to Fe–TiCN around 1400 °C.