Anion Exchange Resin Separation of Gd, Eu, Sm, Nd and Pr in Methanol-Acetic Acid-Nitric Acid Mixtures

Abstract

Ion exchange separation of gadolinium, europium, samarium, neodymium and praseodymium was studied using mixed solutions of methanol-acetatic acid-nitric acid, and those five rare earths we the Amberlyst-A 29 (nitrate form). The rare earths described above were strongly adsorbed on the top of the column from solutions consisting of 90% methanol, 5% glacial acetic acid and 5 % 7 mol/l nitric acid. Then, Gd, Eu, Sm, Nd, and Pr were eluted in this order by passing successively the four kinds of eluents : (flow rate : 0.7.0.8 ml/min)
( 1 ) MeOH-17 mol/l HOAc-7 mol/l HNO₃ (volume ratio : 90 : 5: 5).
( 2 ) MeOH-10 mol/l HOAc-7 mol/l HNO₃ (80 : 15 : 5).
( 3 ) MeOH-8 mol/l HOAc-7 mol/l HNO₃-H₂O (75 : 15 : 5: 5) and ( 4 ) H₂O.
It is confirmed that up to 0.007 mmol of Gd, Eu, Sm, Nd, and Pr are satisfactorily separated with a column of 1.1 cm diameter and 21 cm length.