ISOTACHOPHORETIC SEPARATION OF RARE-EARTH IONS .1. SEPARATION BEHAVIOR OF YTTRIUM AND 14 LANTHANIDE IONS FORMING COMPLEXES WITH TARTARIC ACID AND ALPHA-HYDROXYISOBUTYRIC ACID

A leading electrolyte for the isotachophoretic separation of yttrium ion from lanthanide ions was developed, consisting of 20 mM ammonia solution containing 0.5 mM tartaric acid and 8 mM alpha-hydroxyisobutyric acid (HIB) as complex-forming agents. The pH of the solution was adjusted to 4.8 by adding acetic acid. Using the electrolyte system developed, the separation behaviour of fifteen rare earth ions was studied in comparison with a simple HIB system. It was revealed that the addition of tartaric acid lowered the separability of adjacent pairs of medium and heavy lanthanide ions to two-thirds of that of HIB system, instead of the successful separation of Dy and Y. The electrolyte system developed was applied to the separation of a rare earth ore sample containing Y as one of the major components.