Liquid-liquid extraction of cerium (III) and lanthanum (III) from aqueous chloride solutions by SME 529®

Abstract The extraction of cerium (III) and lanthanum (III) from aqueous chloride solutions by SME 529 dissolved in n-heptane was studied as a function of pH, extractant, metal and chloride concentrations. The extraction equilibrium for both lanthanides was found to depend strongly on pH and SME 529 concentration. The calculated extraction constants are: log K ex = − 16.3 for Ce(III) and log K ex = − 19.5 for La(III). Large extraction coefficient values can be achieved only at relatively high pH values when partial precipitation of hydroxide occurs. CeR 3 and LaR 2 OH are the main species extracted.