Thermodynamic behavior of dissolved oxygen and hydrogen in pure vanadium

• Published in: Journal of mining and metallurgy. Section B, Metallurgy Vol. 57; no. 3; pp. 413 - 419
• Main Authors: Zhong, D.-P., Pei, G.-S., Xiang, J.-Y., Pan, C., Gu, W., Lv, X.-W.
• Format: Journal Article
• Language: English
• Published: Bor Technical Faculty Bor, University of Belgrade 2021; Technical Faculty, Bor
• Subjects: Aluminum; de-oxidation limit; Dissolved oxygen; Energy; Equilibrium; Equilibrium conditions; equilibrium phase; generating gibbs free energy; Hydrogen; Magnesium; Oxidation; Oxygenation; Reducing agents; Silicon; Solid solutions; Temperature; Thermodynamic properties; Thermodynamics; v-h-o solid solution; Vanadium
• ISSN: 1450-5339; 2217-7175
• DOI: 10.2298/JMMB210108037Z

The mechanism governing the deoxidation of vanadium metal is regarded as fundamental knowledge; however, it has not been elucidated in existing literature. In this paper, the thermodynamic data of V-H-O systems were summarized, and the Gibbs free energies of the main compounds were calculated. Consequently, the deoxidation limits of different reductants in a V-O system were evaluated, namely: Si, Al, and Mg. It was observed that Si cannot remove an O content of less than 7.27 wt% from V. However, Al was the stronger reducing agent; it could remove O contents of up to 0.01 and 0.1 wt% at 800 and 1050 ?C, respectively. Nevertheless, Mg exhibited the best reducing properties as it could remove less than 0.01 wt% of O at 1100 ?C. The addition of H2 renders the V-O solid solution unstable to a certain extent, thereby indicating that H2 facilitates deoxygenation. Furthermore, the results obtained by analyzing the equilibrium conditions were in accordance with the results of the deoxidation limit in the V-O system. In other words, this study demonstrates that the oxygen in vanadium can be effectively controlled by changing the reductant dosage and temperature.