Liquid extraction of lithium using a mixture of alkyl salicylate and tri-n-octylphosphine oxide

Alkyl esters (C3-C8) of salicylic acid (HL) together with trioctylphosphine oxide (TOPO) were considered in order to find new lithium-selective extraction agents for liquid extraction. The hydrolytic stability of salicylic acid alkyl esters in lithium extraction processes from alkaline solutions was studied. Factors were found to reduce the hydrolysis of the extractant. Compositions of extractable alkali metals (Li, Na, K) complexes by a mixture of octyl ether of salicylic acid (HL8) with TOPO have been determined. The enthalpy values of the extraction reactions were calculated. Extraction isotherms were obtained and laboratory simulation of lithium extraction from alkaline multicomponent solutions using HL8-TOPO mixture as an extractant was performed.