1. A PROCESS OF SEPARATING CESIUM VALUES FROM AN AQUEOUS MINERAL ACID SOLUTION COMPRISING ADJUSTING THE ACIDITY TO A VALUE WITHIN THE RANGE FROM A PH VALUE OF ABOUT 1.5 TO A MOLARITY OF ABOUT 5, ADDING A METAL-CATION-COBALTICYANIDE PRECIPITATE IN THE SOLUTION, SAID METAL CATION BEING SELECTED FROM THE GROUP CONSISTING OF COBALTOUS, ZINC, CADMIUM, NICKEL AND FERROUS CATIONS WHEREBY THE CESIUM VALUES ARE CARRIED ON THE PRECIPITATE, AND SEPARATING THE PRECIPITATE FROM THE SOLUTION.