Simple chemical method for the separation of rare earth metals

A method for separating, one from another, different metals combined in a source thereof, said metals being selected from the group of rare earth metals consisting of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, the method comprising:

• a) establishing a chemical equilibrium in a polar solvent between complexes of the metals sought to be separated, each complex comprising a rare earth metal ion and a ligand capable of binding to said rare earth metal ion, said complexes including a monomer comprising a rare earth metal ion having a relatively smaller ionic radius and a dimer comprising a different rare earth metal ion having a relatively larger ionic radius when the ionic radii of the rare earth metal ions are compared;
• and either:
• b1) replacing the polar solvent with a non-polar solvent, thereby resulting in a solid-liquid mixture, the solid component of the mixture comprising predominantly the rare earth metal having the smaller ionic radius, and the liquid component of the mixture comprising predominantly the rare earth metal having the larger ionic radius;
• and
• b2) separating said solid component from said liquid component;
• or
• c1) applying an oxidizing electrochemical potential or a chemical oxidizing agent to the complexes of the metals sought to be separated, dissolved in a polar solvent, to selectively oxidize the complex having an earlier rare earth metal ion;
• and
• c2) separating the oxidized, earlier rare earth metal ion complexes through differences in solubility or chemical properties using precipitation-filtration or liquid-liquid extraction.