Abstract: The present invention comprises a process for separating rare earth ions or actinide ions or mixtures thereof in solution by passing the solution through an ion exchange material to separate the rare earths or actinides or mixtures thereof. The ion exchange material has a surface area of about 5-1500 m.sup.2 /g. The ion exchange material is impregnated with a liquid containing alkali metal cations, Group Ib metal cations, ammonium cations, organic amines or mixtures thereof, at a pH range above about 9. A plurality of fractions of the solution is collected as the solution passes through the ion exchange material, preferably in a column. This process is particularly preferred for separating rare earth ions and especially lanthanum and neodymium. It is particularly preferred to purify lanthanum to contain less than 0.1 ppm, preferably less than 0.01 ppm, of neodymium.