Studies on Isotope Separation of Lithium by Electromigration in Fused Lithium Bromide and Potassium Bromide Mixture, (I)

Enrichment of Lithium-7

Abstract

Lithium-7 was enriched by electromigration at 500°C in fused LiBr-KBr mixture.
The migration cell was made of Pyrex glass; zircon sand (100200 mesh) was used for packing material, and graphite rods as electrodes.
The electromigration was carried out for 13.4 days at a constant electric current of 165 mA. The distribution of the abundance ratio of the Li isotopes and of the composition of the salt in the migration cell were investigated. The abundance ratio of the Li isotopes (⁷Li/⁶Li) in the anode compartment was found to change from the original value of 12.20 to 46.9. The com-position (Li/K in chemical equivalent ratio) of the salt reached roughly constant at 1.41 through-out the migration cell except in the vicinity of the cathode, and the value was not affected by the composition of the feed salt. It is the selective transport of salt of this composition toward the anode compartment by capillary action in the migration cell that is considered the mechanism that makes sustained electromigration possible. The mechanism of the accumulation of the iso-tope effect is also discussed.