Complex formation of light and heavy lanthanides with DGA and DOODA, and its application to mutual separation in DGA-DOODA extraction system

DGA, DOODAを用いる軽、重希土類元素の錯形成とLn相互分離への適用

野水 大輝; 佐々木 祐二  ; 金子 政志   ; 松宮 正彦*; 勝田 正一*

Nomizu, Daiki; Sasaki, Yuji; Kaneko, Masashi; Matsumiya, Masahiko*; Katsuta, Shoichi*

我々は水溶性のジグリコールアミド(DGA)とジオキサオクタンジアミド(DOODA)による希土類元素の逐次錯形成を溶媒抽出系で調べた。抽出剤であるTODGAとDOODA(C8)はLnパターン(Ln分配比と原子番号の関係)の逆相関を示し、その組み合わせは相互分離に有効である。水系でDOODAは2分子、DGAは3分子希土類に配位することが分かった。1010段の多段抽出を実施し、La, Pr, Ndは水相に、一方Sm-Dyは有機相に分離することができた。

We studied the successive formation of water soluble DGA (diglycolamide) and DOODA (dioxaoctanediamide) for the mutual separation of Ln in this extraction system. TODGA (tetraoctyl-diglycolamide) and DOODA(C8) (tetraoctyl-dioxaoctanediamide) have the opposite trend to extract light and heavy Ln through Ln-patterns. Metal-complexes of two folding Ln ions with water-soluble DOODA and three folding with DGA are found and their observed formation constants are calculated. The suitable separation condition (aqueous phase: 30 mM DOODA(C2) in 1 M nitric acid, organic phase: 0.1 M TODGA in n-dodecane) of multi-stage extraction (10 10) is conducted. From the present work, it is clear that La, Pr and Nd are mainly present in aqueous phase, instead Sm-Dy exist in the organic phase.