A selective separation of Tc, Np and U from a simulated radwaste solution was carried out by a solvent extraction using 30% vol. tributyl phosphate (TBP)/n-dodecane, where a small amount of tri-n-octylamine(TOA) was added in order to enhance the extraction yield of Tc. Co-extraction of Tc, Np and U by 30% TBP-0.5% TOA/n-dodecane from the 10 components solution that contained the 0.005 M K_2Cr_2O_7 as an oxidant of Np, and selective stripping of Tc, Np and U from the loaded organic phase were investigated and their operation conditions were evaluated. Tc, Np and U were effectively co-extracted at O/A=1 and 1M HNO_3. Co-extraction yields of Tc, Np and U were 81.5%, 84.8%, 88.6%, respectively, and those of Am, Eu, Nd, Mo, Fe, Cs and Sr were below 4%. On the other hand, the co-extracted Tc, Np and U can be separated selectively and effectively by following the subsequent stripping steps: the stripping of Tc with 5 M HNO_3 (O/A=2), the reduction stripping of Np(Ⅵ) with 0.05 M acetohydroxamic acid (O/A=3), and the stripping of U with 0.15 M Na_2CO_3 (O/A=1). In this case, 78.9% of Tc (co-stripping of 3.6% Np and 0.6% U), 95.7% of Np(co-stripping of 3.8% U), and above 99% of U will be recovered, respectively.

30% vol. TBP/n-dodecane에 소량의 TOA (tri-n-octylamine)를 첨가하여 Tc의 추출을 증진시키면서 Tc, Np 및 U만 선택적으로 분리하는 연구를 수행하였다. NP의 산화제로 0.005 M K_2Cr_2O_7이 함유된 10성분계 모의방사성 폐액을 대상으로 30% TBP-0.5% TOA/n-dodecane에 의한 Tc, Np 및 U의 공추출과 공추출된 유기상으로부터 이들의 선택적 역추출 및 이의 조업조건을 고찰하였다. 공추출은 질산농도 1 M, 상비(O/A) 1에서 효과적이며, 이때 Tc은 81.5%, Np은 84.8%, 은 U=88.6%, Am, Eu, Nd, Mo, Fe, Cs, Sr 등은 모두 4% 이하가 공추출되었다 반면에 공추출된 Tc, Np 및 U의 선택적 역추출은 우선 5 M 질산(O/A=2)으로 Tc을 역추출한 다음, 0.05 M AHA (acetohydroxamie acid, O/A=3)로 Np을 환원 역추출하고, 마지막으로 0.15 M Na_2CO_3(O/A= 1)로 U을 역추출하면 효과적으로 이들을 개별 분리할 수 있다. 이때 Tc은 1단 기준 78.9%(Np=3.6%, U=0.6% 공역추출), Np은 95.7% (U=3.8% 공역추출), U은 99% 이상을 각각 회수할 수 있다.