| 摘要 |
"Rare earth metal" ions are separated by ion-exchange chromatography in which process an aqueous eluent capable of forming complex compounds with "rare earth metal ions" to be separated is contacted with a bed of cation exchange resin containing said ions, the eluent thereafter being contacted with a further bed of cation-exchange resin containing ions of at least one further "rare earth metal" capable of forming with the eluent a complex of greater stability than any of the complexes formed with the "rare earth metal" ions to be separated and thereafter recovering the "rare earth metal" ions to be separated. The preferred aqueous eluent contains ethylenediamine tetracetic acid or nitrolotiracetic acid, and the further "rare earth metal" ions are of higher atomic weight than the "rare earth metal" ions to be separated and especially consist of at least one "zttrium compound" i.e. a rare earth of atomic weight of at least 152 and includes zttrium itself in addition, although not a rare earth by the usual definition. The invention is described with reference to two examples using ammonium nitrolotriacetate and ammonium ethylene diamine tetraacetate as eluting agents. |
