Mutual separation of Ln and An using TODGA and DTBA with high organic acid concentrations

有機酸を含む溶液からTODGAとDTBAを用いるLnとAnの相互分離

佐々木 祐二  ; 金子 政志   ; 松宮 正彦*; 中瀬 正彦*; 竹下 健二*

Sasaki, Yuji; Kaneko, Masashi; Matsumiya, Masahiko*; Nakase, Masahiko*; Takeshita, Kenji*

イオン半径の酷似する3価Ln, An分離は今でも挑戦的な研究である。ここでは、TODGAとDTBA(ジエチレントリアミントリ酢酸ジアミド)を使っての相互分離を検討した。過去の結果から我々はより安定な分離条件設定と高い分離性能を得ることを目的とした。希硝酸、DTBA濃度とpH緩衝液の乳酸を使ってpH条件を安定化した。その結果、有機相には97.1% Ndと1.59% Amを、及び水相には98.4% Amと2.95%のNdを分離回収できることを確認した。

Owing to the chemical behavior of trivalent lanthanide and actinide ions with similar ionic radii, realizing this separation is still challenging. All lanthanides, Am, and Cm can be extracted using diglycolamide (DGA), and relatively high An/Ln separation efficiencies have been obtained using diethylenetriamine-triacetic-bisamide (DTBA). To improve the previous results as well as the separation conditions, we used organic acids for pH adjustment. The advantages of this modification included low HNO, DTBA concentrations and pH stability owing to the addition of lactic acid. Under these modified conditions, the recovery rates observed were as follows: 97.1% for Nd with the co-existence of 1.59% Am in organic phase, and 98.4% for Am with the co-existence of 2.95% Nd in aqueous phase.