The extraction of Zn(II) from 1.0 M KCl by Cyanex 302 dissolved in tol
uene was studied as a function of the total extractant concentration,
the equilibrium pH and the total metal concentration. Experimental dat
a, treated both graphically, using curve-fitting analysis, and numeric
ally, by the computer program LETAGROP-DISTR, can be explained by assu
ming the extraction of the species ZnClR(HR), ZnR(2)(HR)(2), ZnL(2) an
d ZnL(2)(HL) (HR)(3), where (HR) stands for bis(2,4,4-trimethylpentyl)
monothiophosphinic acid, the active component of Cyanex 302, and (HL)
represents bis(2,4,4-trimethylpentyl)dithiophosphinic acid, the active
component of Cyanex 301 extractant, which is present in commercial Cy
anex 302 as a minor component.