Abstract: Distribution coefficients have been measured for the partition of metal ions between cation exchange resin and acetone-water-hydrochloric acid solutions. the differences in distribution coefficients of metal ions are greater in acetone-water media than in aqueous media of the same hydrochloric acid concentration. Using distribution coefficient data, conditions for column separations of mixtures can be selected. Column separations of metal ion mixtures can be effected by eluting with acetone-water-hydrochloric acid solutions of different compositions. Successful separations of a number of mixtures are reported.