Process for separating rare earths and yttrium by ion exchange

Claim 1

A METHOD OF SEPARATING RARE EARTH METALS AND YTTRIUM FROM EACH OTHER BY ION EXCHANGE, COMPRISING THE STEPS OF CONTACTING AN AQUEOUS SOLUTION CONTAINING RARE EARTH METAL AND YTTRIUM IONS WITH A FIRST ION EXCHANGE RESIN ADAPTED TO ADSORB SAID ION, THEREBY CHARGING SAID ION EXCHANGE RESIN WITH ADSORBED RARE EARTH METAL AND YTTRIUM IONS; PASSING A SOLUTION OF A COMPLEXING AGENT ADAPTED TO FORM COMPLEXES WITH SAID RARE EARTH AND YTRIUM AND BEING SELECTED FROM THE GROUP CONSISTING OF ETHYLENEDIAMINE TETRAACETIC ACIDK, ALKALI METAL AND AMMONIUM SALTS OF EHTYLENEDIAMINE TETRAACETIC ACID, NITRILOTRIACETIC ACID, HYDROXYETHYLENEDIAMINE TRIACETIC ACID, DIETHYLENETRIAMINE PENTAACETIC ACID AND DIAMINOCYCLOHEXANE TETRAACETIC ACID THROUGH SAID CHARGED FIRST ION EXCHANGE RESIN SO AS TO FORM A FIRST ELUATE CONTAINING COMPLEXES OF SAID COMPLEXING AGENT AND SAID RARE EARTH METALS AND YTTRIUM; PASSING SAID FIRST ELUATE THROUGH A SECOND ION EXCHANGE RESIN CHARGED WITH LOWER METAL IONS SELECTED FROM THE GROUP CONSISTING OF ZINC AND CADMIUM IONS SO AS TO FORM LOWER METAL COMPLEXES OF SAID LOWER METAL IONS AND SAID COMPLEXING AGENT, THEREBY FORMING A SECOND ELUATE CONTAINING SAID LOWER METAL COMPLEXES OF SAID LOWER METAL IONS AND SAID COMPLEXILNG AGENTS AND SAID RARE EARTHS AND YTTRIUM COMPLEXES; AND COLLECTING SUCCESSIVE PORTIONS OF SAID SECOND ELUATE SO AS TO SEPARATELY OBTAIN THE INDIVIDUAL RARE EARTHS AND YTTRIUM AND SAID LOWER METAL COMPLEXES.

Claim 2

A METHOD OF SEPARATING RARE EARTH METALS AND YTTRIUM FROM EACH OTHER BY ION EXCHANGE, COMPRISING THE STEPS OF CONTACTING AN AQUEOUS SOLUTION CONTAINING RARE EARTH METAL AND YTTRIUM IONS WITH A FIRST ION EXCHANGE RESIN ADAPTED TO ADSORB SAID ION, THEREBY CHARGING SAID ION EXCHANGE RESIN WITH ADSORBED RARE EARTH METAL AND YTTRIUM IONS; PASSING A SOLUTION OF A COMPLEXING AGENT ADAPTED TO FORM COMPLEXES WITH SAID RARE EARTH AND YTRIUM AND BEING SELECTED FROM THE GROUP CONSISTING OF ETHYLENEDIAMINE TETRAACETIC ACIDK, ALKALI METAL AND AMMONIUM SALTS OF EHTYLENEDIAMINE TETRAACETIC ACID, NITRILOTRIACETIC ACID, HYDROXYETHYLENEDIAMINE TRIACETIC ACID, DIETHYLENETRIAMINE PENTAACETIC ACID AND DIAMINOCYCLOHEXANE TETRAACETIC ACID THROUGH SAID CHARGED FIRST ION EXCHANGE RESIN SO AS TO FORM A FIRST ELUATE CONTAINING COMPLEXES OF SAID COMPLEXING AGENT AND SAID RARE EARTH METALS AND YTTRIUM; PASSING SAID FIRST ELUATE THROUGH A SECOND ION EXCHANGE RESIN CHARGED WITH LOWER METAL IONS SELECTED FROM THE GROUP CONSISTING OF ZINC AND CADMIUM IONS SO AS TO FORM LOWER METAL COMPLEXES OF SAID LOWER METAL IONS AND SAID COMPLEXING AGENT, THEREBY FORMING A SECOND ELUATE CONTAINING SAID LOWER METAL COMPLEXES OF SAID LOWER METAL IONS AND SAID COMPLEXILNG AGENTS AND SAID RARE EARTHS AND YTTRIUM COMPLEXES; AND COLLECTING SUCCESSIVE PORTIONS OF SAID SECOND ELUATE SO AS TO SEPARATELY OBTAIN THE INDIVIDUAL RARE EARTHS AND YTTRIUM AND SAID LOWER METAL COMPLEXES.