The lithium oxide solubility in molten fluoride system CeF3 - FLiNaK

Molten systems based on alkali metal halides with lithium oxide additives are promising as a working medium on pyrochemical reprocessing of nuclear waste. A mixture of alkali metal fluorides of eutectic composition (FLiNaK) is a suggested solvent due to the high solubility of actinide oxides, low vi...

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Bibliographic Details
Main Authors: Zakiryanova Irina, Korzun Iraida, Nikolaeva Elena, Bovet Andrey
Format: Article
Language:English
Published: Serbian Chemical Society 2025-01-01
Series:Journal of the Serbian Chemical Society
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Online Access:https://doiserbia.nb.rs/img/doi/0352-5139/2025/0352-51392400038Z.pdf
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Summary:Molten systems based on alkali metal halides with lithium oxide additives are promising as a working medium on pyrochemical reprocessing of nuclear waste. A mixture of alkali metal fluorides of eutectic composition (FLiNaK) is a suggested solvent due to the high solubility of actinide oxides, low viscosity, high boiling points, low vapor pressure and resistance to radiation damage. Thermal analysis, XRD, Raman spectroscopy and thermodynamic simulations were used to obtain evidences on the phase equilibria and liquidus points of the system (0.85 FLiNaK–0.15 CeF3)–Li2O, containing up to 8.8 mol. % lithium oxide. The solubility of lithium oxide in the fluoride melt FLiNaK– –CeF3 and the thermodynamic parameters of dissolution were obtained. The eutectic point (the Li2O content is 3.1 mol. %, Tm = 489 °С) and two peritectic points (lithium oxide content are 3.2 and 4.2 mol. %, and liquidus points are 497 and 549 ºС, respectively) were found. Thermodynamic simulation results show an exothermic effect due to interaction between lithium oxide and fluoride melt. The interaction product oxyfluoride CeOF was detected by XRD analysis and Raman spectroscopy.
ISSN:0352-5139
1820-7421