REDUCTIVE EXTRACTION BEHAVIOR OF ACTINIDE AND LANTHANIDE ELEMENTS IN MOLTEN-SALT AND LIQUID-METAL BINARY PHASE SYSTEMS

In support of the development of a pyrochemical group-partitioning pro cess of actinides and lanthanides, the equilibrium distributions of th ese elements were measured in some binary phase systems of molten salt and liquid metal. An LiF-BeF2, mixture was selected as the salt phase and Bi, Sn, Cd and Zn were examined as the metal phase. In general, a ctinides were more easily reduced and extracted from the salt phase in to the metal phase than were lanthanides. Group partitioning is thus f easible. In different partitioning systems a systematic difference in the separation factor between actinides and lanthanides was observed. The difference is attributable to the difference in alloying energies in the metal phase. The thermodynamic quantities of solute elements in the metal phase were evaluated from the present analysis. Some regula rities were inferred from the analysis which are theoretically interes ting and helpful to estimate unknown distribution coefficients.