Preparation of vanadium by the magnesiothermic self-propagating reduction and process control

Abstract

Abstract A new process for preparing vanadium by direct reduction of V2O5 from the Mg–V2O5 self-propagating system is proposed in this article. The reaction behavior and path of V2O5 in the magnesiothermic reduction process were investigated using the XRD, SEM-EDS, laser particle size analyzer, and specific surface area analyzer. The experimental results show that the reaction of the V2O5–Mg system is a solid-solid reaction, and the initial reaction temperature is 570°C. Although the formation of MgV2O4 spinel cannot be predicted via the calculation of thermodynamics, the presence of MgV2O4 spinel is of great significance to the V2O5 reduction process. Taking into account the characteristics of the gradual reduction of V2O5 by Mg and the appearance of the MgV2O4 spinel phase, the limiting link of the reaction may be the transition from MgV2O4 to V. A reduction path of V2O5 beyond the thermodynamic prediction is proposed: V2O5 → V3O5 → MgV2O4 → V. The reaction temperature and the phase transformation process can be effectively controlled by adjusting the ratio of reactants and additives, and element V can be obtained by a one-step rapid self-propagating reaction and breaking through the reaction restriction link. In this experiment, the vanadium powder with a porous structure, a specific surface area of 3.44 m2 g−1, and the oxygen content of 4.86 wt% were obtained.