Systematics of the thermodynamic properties of trivalent f-elements in a pyrometallurgical bi-phase extraction system

In order to strengthen the comprehensive understanding on the mechanism of the extraction of f-elements in a pyrometallurgical bi-phase extraction sys tem, which is usable for dry-reprocessing of spent nuclear fuels, some ther modynamic quantities related to their affinity to the solvent materials wer e studied. A reductive extraction system consisting of molten alkaline chlo ride and liquid Pi and Zn was selected for this purpose, and the excess fre e energy of tri-chlorides of lanthanides associated with their solution int o alkaline chloride molten salt was estimated. The standard Gibbs energy ch ange of formation of diluted liquid alloy of lanthanides with Pi and Zn was discussed with the aid of a semi-empirical model for alloy formation. Thei r systematic variations along the f-series were studied to elucidate the di stribution behaviors. (C) 2000 Elsevier Science B.V. All rights reserved.