Carbothermic Reduction and Nitridation Mechanism of Vanadium-Bearing Titanomagnetite Concentrate

In this study, the carbothermic reduction and nitridation mechanism of vanadium-bearing titanomagnetite concentrate are investigated in terms of phase transformation, microstructure transformation, and thermodynamic analyses. The differences in the reaction behavior of titanomagnetite and ilmenite in vanadium-bearing titanomagnetite concentrate, as well as the distribution characteristic of V in the roasted products, are emphatically studied. It is observed that the reaction sequences of titanomagnetite and ilmenite transformations into nitride are as follows: Fe3-xTixO4 -> Fe2TiO4 -> FeTiO3 -> M3O5 ->(Ti, V)(N, C); FeTiO3 -> M3O5 -> Ti(N, C). The reduction of M3O5 to TiN is the rate-limiting step of the entire reaction, and metal iron is an important medium for transferring C for the reduction of M3O5. Titanomagnetite is faster to convert into nitride than ilmenite is, and the reasons for this are discussed in detail. During the entire roasting process, V mainly coexists with Ti and seems to facilitate the conversion of titanium oxides into (Ti, V)(N, C).

Automated summary

This study investigates the carbothermic reduction and nitridation mechanism of vanadium-bearing titanomagnetite concentrate in terms of phase and microstructure transformation, as well as thermodynamic analyses. It is observed that titanomagnetite converts into nitride faster than ilmenite, and the role of V in facilitating the conversion of titanium oxides is discussed in detail.