Isotope enrichment by thermal diffusion in fused alkali nitrates

Department of Physics, Chalmers University of Technology, Gothenburg, Sweden, Sweden.

Abstract

Thermal diffusion has been studied in fused nitrates. In the pure salts LiNO₃ and RbNO₃ the ratios ⁶Li/⁷Li and ⁸⁵Rb/⁸⁷Rb were highest on the hot side. The Soret coefficients were found to be 3,3.10^-5 degrees^-1 (temperature region 276-425 degr. C) and 1,0.10^-5 degrees^-1 (335-483 degr. C) respectively. A number of mixtures of LiNO₃ and AgNO₃ were investigated in a thermogravitational column. In a run with 60 mole % LiNO₃, a cell height of 9,4 cm, a plate distance of 0,023 cm, and a temperature difference between the plate surfaces of about 29 degrees a separation factor of 1,043 was obtained after 120 hours, with ⁶Li enriched at the top.