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Phase equilibria and thermodynamics of the system Dy-Mg-Cl at 1073 K

Uda, Tetsuya and Okabe, Toru H and Waseda, Yoshio and Jacob, KT (1999) Phase equilibria and thermodynamics of the system Dy-Mg-Cl at 1073 K. In: Journal of Alloys and Compounds, 284 (1-2). pp. 282-288.

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Official URL: http://dx.doi.org/10.1016/S0925-8388(98)00944-X

Abstract

The phase relations in the system Dy–Mg–Cl at 1073 K have been established by isothermal equilibration and chemical analysis of quenched samples. Liquid Mg-rich alloy was found to be in equilibrium with molten DyCl2. Therefore, DyCl2 can be synthesized by reduction of MgCl2 with excess of metallic Dy at 1073 K. The Gibbs energy of formation of DyCl2 at 1073 K was evaluated by two different methods. From voltammetric determination of decomposition voltage, the upper limit for the standard Gibbs energy of formation of DyCl2 was estimated to be −505(±20) kJ mol−1. A value of −543(±10) kJ mol−1 was deduced from phase relations using Gibbs–Duhem integration. The value for the standard Gibbs energy of DyCl2 indicates that the Dy2+ ion has a potential capability for reducing TiCl4 to metal titanium. At the same time, Mg is a reductant for Dy3+ produced during the reduction of TiCl4. Thus, it is thermodynamically confirmed that reduction of TiCl4 by magnesium using a reaction mediator in the salt phase is feasible.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Elsevier Science.
Keywords: Rare earth;Dysprosium;Dichloride;Thermodynamics;Titanium production
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited: 27 Feb 2012 11:41
Last Modified: 27 Feb 2012 11:41
URI: http://eprints.iisc.ernet.in/id/eprint/42697

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