Carbothermic Reduction and Nitridation Mechanism of Vanadium-Bearing Titanomagnetite Concentrate

Wen Yu,Wei Liu,Jiangan Chen,Xiaojin Wen

doi:10.3390/min11070730

Abstract

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).

Highlights

This finding is in line with previous studies that showed that the majority of V in Vanadium-bearing titanomagnetite concentrate (VTMC) exist as V3+, which substitutes for Fe3+ in magnetite lattice
The results show that the main phases of the roasted pellets were Figure 3. 5—iron (Fe), M3 O5, and MgAl2 O4 when the roasting time was 10 min, indicating that the reduction reactions of Fe3− x TixO4 and FeTiO3 to Fe and M3 O5 were essentially completed
V mainly coexisted with Ti during the entire reactions and formed (Ti, V)(N, C), while a small amount of V was enriched in the sulfur inclusions of metallic iron

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Vanadium-bearing titanomagnetite is an important mineral resource, and it is rich in titanium (Ti), iron (Fe), and vanadium (V). It widely exists in Russia, China, South Africa, the United States of America, and New Zealand [1]. In China, the deposit of vanadiumbearing titanomagnetite is more than 18 billion tons in the Panxi and Chengde districts

Methods

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Discussion

Conclusion