Solubility of Rare Earth Oxides in Fused Alkali and Alkaline Earth Halides

Abstract

Solubility of rare earth oxides in mixtures of alkali or alkaline earth halides was determined by the method of isothermal saturation at the temperatures up to 1400oC. The melts studied included CaCl2–CaF2 (20 or 75 mol. % CaF2), BaCl2–BaF2 (15 or 73 mol. % BaF2), equimolar CaF2–BaF2 and eutectic NaCl–NaF mixtures. Melting points of the salt mixtures were determined by differential thermal analysis and effect of added rare earth oxide on the melting point was considered. Solubility of yttrium, lanthanum, cerium, praseodymium, neodymium, and samarium oxides was determined. The effect of temperature, melt composition, and presence of a mixture of rare earth oxides on solubility was assessed.

Reaction of Oxygen with Uranium (IV) Chloride in Fused Alkali Chlorides

“…[1][2][3][4] Depending on the experimental conditions the reaction led to precipitation of rare earths as oxychlorides or oxides, with higher temperatures favoring the oxide formation. 2,4 Low solubility of rare earth oxides in halide melts 5,6 allows proposing this method, for example, for removing rare earth fission products from chloride electrolytes.…”