The isotope effects in the isotope exchange equilibria of lithium in the amalgam-solution system

Abstract

The elementary separation factors for lithium isotopes in the isotope-exchange equilibria between the amalgam and the organic solution have been measured at several temperatures between −15 and 85°C. DMSO, DMA and DEF were employed as the organic solvents for lithium salts. The separation factors with these systems have been found to be larger than those reported previously with other chemical exchange systems. Lithium-6 has been enriched in the amalgam phase in all the systems studied. The separation factors vary from 1·085 to 1·028, decreasing with an increase in the temperature. By plotting the logarithm of the separation factors vs the reciprocal of the square of the temperature, a nearly linear correlation was obtained. In the systems employing DMSO, the separation factors decrease in the following order: α CH 3COOLi ≈ α LiI ≈ α LiBr > α LiCl > α LiNO 3 . The kind of the organic solvent has been found to affect the separation factor. The separation factors for the DMA or the DEF solution systems are larger than those for the DMSO-solution systems over the range of temperature investigated. The large separation factors obtained in these experiments indicate that the present isotope-exchange process may be suitable for the enrichment of lithium isotopes.