Novel approach to prepare Fe-TiN cermets from ilmenite concentrate using clean NH3 gas.

Fe-based cermets are of considerable research interest owing to their excellent physical and mechanical properties. In this study, a new process for the reduction and nitridation of Panzhihua ilmenite using NH 3 was proposed to prepare Fe-TiN composites, and the process was deemed feasible by thermodynamic calculations. The final products, Fe and TiN, could be formed based on the reaction conditions. The experimental results validated that metallic Fe could be easily formed, while MgTiO 3 was more difficult to reduce than FeTiO 3. The final products of Fe/TiN/MgO obtained at 1373–1473 K were consistent with those from the thermodynamic analysis. By increasing the reduction temperature or duration, the Fe particles increased in size and mixed with the TiN particles. The elemental content of Mg, Al, and Ca in the magnetic product was 5.85 wt% after magnetic separation. A Fe-TiN cermet was prepared from the magnetic product by hot-pressing (HP) sintering. Fe and TiN were uniformly distributed in the cermet, and the hardness of the obtained cermet reached 18.2 GPa. This work could offer a new approach to the preparation of Fe-based cermets from low-grade ilmenite. [Display omitted] • A novel method for synthesizing Fe–TiN composites from low–grade ilmenite is proposed. • Clean ammonia gas is used as reduction and nitridation agent. • The phase transformation and microstructure evolution of ilmenite during the reduction roasting process are studied. • The Fe–TiN cermet with a hardness of 18.2GPa is prepared by hot pressing (HP) sintering. [ABSTRACT FROM AUTHOR]