The extraction of lithium chloride by tri-n-butyl phosphate

Abstract

The extraction of lithium chloride from aqueous solutions by tri-n-butyl phosphate (TBP) has been investigated. Lithium chloride in the organic phase behaves as an associated electrolyte with a dissociation constant ∼5 × 10 −6. It has been shown that up to ca. 0·96 M LiCl in the organic phase there is no strong TBP-salt interaction but there appears to be a definite tendency for the extracted lithium chloride to possess a primary hydration number of four. At higher concentrations, TBP molecules begin to substitute for H 2O molecules in the solvation shell of the extracted LiCl but a total solvation number of four seems to be maintained. Physical properties suggest the possibility of aggregation in the most concentrated extracts.