GB1115929A - Enrichment of isotopes of lithium - Google Patents

Abstract

<PICT:1115929/C1/1> A process for enriching lithium isotopes by selective distribution into two liquids which are in contact with each other, comprises contacting lithium amalgam with a solution of a lithium salt in at least one organic amine solvent with a boiling point below 100 DEG C., e.g. propylamine, isopropylamine and ethylamine. In practice, the lithium amalgam is fed into the top end of an exchange column 1 and is contacted with a solution of the lithium salt in the organic amine, which salt is derived from an ion exchange reaction in the lower part 13 of the column between the lithium amalgam and a less basic auxiliary salt solution, e.g. CdCl2, CdBr2, ZnBr2 or HgCl2 supplied to the bottom of the column 1 from a column 4. The auxiliary salt solution, e.g. CdCl2 is diluted with recycled amine so as to be present in slightly less than the quantity of lithium supplied. The remaining lithium amalgam, withdrawn together with the cadmium amalgam, is exchanged in a column 2 with further cadmium chloride supplied from a column 5. The cadmium amalgam from this column is reacted in a column 3 with hydrochloric acid to liberate mercury and recover cadmium chloride which is recycled to the columns 4 and 5. The mercury is cycled to an electrolysis apparatus 9 where it is converted to lithium amalgam by electrolysis of an aqueous lithium chloride solution which is procured at 8 from a fractionating column 6. The lithium chloride containing amine solution withdrawn from the top of the column 1, is introduced into boiling water in the bottom of the column 6 and anhydrous amine is withdrawn at 7 at the upper end of the column and recycled to dilute the cadmium chloride solution, whilst the aqueous salt solution is cycled to the electrolysis apparatus. Lithium amalgam having an enriched Li6 content is withdrawn at a point 11 and lithium chloride having an enriched Li7 content is withdrawn at a point 12. A quantity of lithium equal to the total quantity withdrawn is supplied to a point in the column 1 where the concentration of enriched Li6 is approximately equal to the concentration of unenriched lithium.