Method of extraction separation of cesium cations from aqueous solution thereof

The extraction is effected using a metallo-dicarbollide anion solution in a polar organic solvent, to advantage in nitrobenzene, nitrotoluene, nitropropane, nitromethane or dinitrochlorobenzene. The organic solvent is diluted with a nonpolar solvent, e.g., tetrachloromethane, benzene or toluene. The organic phase is extracted by means of a mineral acid aqueous solution at a concentration of 0.5 to 14 mol/l or an ammonium salt aqueous solution at a concentration between 0.5 mol/l to saturation. (J.P.)