Thermodynamic behavior of dissolved oxygen and hydrogen in pure vanadium

J. Min. Metall. Sect. B-Metall., 57 (3) (2021) 413-419 DOI:10.2298/JMMB210108037Z
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Available online 03 September 2021
(Received 08 January 2021; Accepted 12 July 2021)
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Abstract

The mechanism governing de-oxidation 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 de-oxidation limits of different reductants in a V-O system were evaluated, namely: Si, Al, and Mg. It was observed that Si could not 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 rendered the V-O solid solution unstable to a certain extent, thereby indicating that H2 facilitated de-oxygenation. Furthermore, the results obtained by analyzing the equilibrium conditions were in accordance with the results of the de-oxidation limit in the V-O system. In other words, this study demonstrated that oxygen in vanadium can be effectively controlled by changing the reductant dosage and temperature.

Keywords: V-H-O solid solution; Generating Gibbs free energy; De-oxidation limit; Equilibrium phase
Correspondence Address:
X.-W. Lv,
a The State Key Laboratory of Mechanical Transmissions, Chongqing University, Shapingba District, Chongqing, China; b College of Materials Science and Engineering, Chongqing University, Shapingba District, Chongqing, China; c Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New Materials, Chongqing University, Chongqing, China; ,
email: This email address is being protected from spambots. You need JavaScript enabled to view it.

 

 

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