Thermodynamic Properties of Ln-O (Ln=La, Pr, Nd) Solid Solutions and Their Deoxidation by Molten Salt Electrolysis.

DOI Web Site 11 Citations 23 References
  • OKABE Toru H.
    Reasearch Associate, Institute for Advanced Material Processing, Tohoku University, Aoba–ku, Sendai 980–8577, Japan
  • HIROTA Koichi
    Graduate Student, Tohoku University, Sendai, Japan (currently Shinetsu Chemical Co. Ltd.)
  • WASEDA Yoshio
    Professor, Institute for Advanced Material Proccssing, Tohoku University
  • JACOB K. T.
    Visiting Professor, Institute for Advanced Material Processing, Tohoku University, on scholastic leave from Department of Metallurgy, Indian Instiltute of Science, Bangalore, India

Bibliographic Information

Other Title
  • Thermodynamic Properties of Ln-O Ln La

Search this article

Abstract

The lanthanide metals lanthanum, praseodymium and neodymium containing 2,200, 2,600, 1,850 mass ppm oxygen, respectively, were deoxidized to 20-30 ppm level at 1,073 K by an electrochemical method. The metal to be deoxidized was used as the cathode in an electrolysis cell which consisted of a graphite anode and molten CaCl2 electrolyte. The calcium metal produced at the cathode by electrolysis effectively deoxidized the lanthanide metal. Calcium oxide produced by deoxidation, dissolved in the melt. The liberation of carbon monoxide/dioxide at the anode was found to prevent accumulation of oxygen in the melt. For a quantitative discussion of the limits of deoxidation achievable by this technique, a thermodynamic investigation of the lanthanide-oxygen (Ln-O ; Ln = La, Pr, Nd) solid solutions was conducted. The lanthanide metal, yttrium and titanium samples were immersed in calcium-saturated CaCl2 melt, containing a small quantity of dissolved CaO, at 1,093 K. The oxygen potential of the melt and the Ln-O solid solutions were obtained from the oxygen content of yttrium samples at equilibrium, and the known thermodynamic properties of yttrium-oxygen solid solution. The results were confirmed by using Y/Y2O3 equilibrium to control the oxygen potential of the molten salt reservoir. The oxygen affinity of the metals was found to decrease in the order : Y > Ti > Nd > Pr > La. The deoxidation results are consistent with the thermodynamic properties of the RE-O solid solutions.

Journal

  • Shigen-to-Sozai

    Shigen-to-Sozai 114 (11), 813-818, 1998

    The Mining and Materials Processing Institute of Japan

Citations (11)*help

See more

References(23)*help

See more

Keywords

Details 詳細情報について

Report a problem

Back to top