화학공학소재연구정보센터
홈 로그인 로그아웃 연락처 사이트맵
HWAHAK KONGHAK, Vol.37, No.6, 897-903, December, 1999
Export Citation
TBP 추출제에 의한 Neptunium의 산화 추출 거동
Extraction and Oxidation of Neptunium from the Simulated Solution by TBP(tributyl phosphate)
이일희, 임재관, 김광욱, 권선길, 유재형, 박현수
초록
TBP추출제에 의한 Np의 추출률은 산화제의 첨가 여부에 관계없이 질산 농도 증가에 따라 증가하였다. 산화제가 첨가되지 않은 경우 2M 질산에서 약 12%가 추출되었으며 4M 질산에서는 불균등화 반응에 의거 약 56%가 추출되었다. 그러나 1g/L 의 NH4VO3 산화제가 첨가된 경우는 Np(V)가 Np(VI)로 산화되어 2M 질산에서도 약 75%가 추출되었다. 그리고 Np에 U이 단독으로 첨가된 경우 Np의 추출률은 U농도 증가에 따라 감소하며, 10g/L의 U 경우 약 66.3%가 추출되었다. 반면에 Zr의 경우 Zr의 농도 증가에 따라 88±2%가 추출되어 Zr의 농도에는 거의 영향이 없었으며, Np이 단독으로 존재할 추출률인 75%보다 약 13-15% 정도 증가되는 상승 효과를 보이고 있다. U과 Zr이 함께 공존하고 있는 경우 또한 Zr의 농도에는 거의 영향이 없었으나 U의 농도 증가에 따라 추출률이 감소하였다. U농도가 5g/L 이하에서는 Zr에 의한 상승 효과로 88±2%가 추출된 반면에, U의 농도가 10g/L에서는 Zr에 의한 상승 효과와 U농도 증가에 따른 감소 효과에 의해 82±1%가 추출되었다. 마지막으로 9성분계에서의 Np 및 U의 추출률은 각각 89%, 93%였고 기타 Zr, Fe, Mo, Nd, Y, Cs 및 Sr 등은 약 5% 미만이 추출되었다.
The extraction yields of Np(ENp) by solvent extraction with tribuyl phospate in n-dodecane(TBP/NDD) increased with concentration of HNO3 regardless of oxidant. Without oxidant, ENp was about 12% at 2 M HNO3 and increased to 56% at 4 M HNO3 due to the disproportionation of Np(V) to Np(VI) and Np(VI). Adding the NH4VO3 of 1 g/L, as a oxidant, ENp was about 75% at 2M HNO3. This was attributable to the oxidation of Np(V) to Np(VI). In the presence of U or Zr, ENp decreased with concentration of U and was about 66.3% at U of 10 g/L. On the other hand, ENp had no effect with concentration of Zr and was in the range of 88±2%. It was found that ENp adding Zr was more enhanced about 13-15% than that of Np only. In the presence of both U and Zr, ENp also had no effect with concentration of Zr and slightly decreased with concentration of U. When U was less than 5 g/L, ENp was in the range of 88±2% by the synergetic effect of Zr only. At U of 10g/L, however, ENp was 82±1% by the synergetic effect of Zr and decreasing effect of U. In the 9 components system containing the NH4VO3 of 1g/L, the extraction yields of Np and U were about 89% and 93%, respectively, and those of Fe, Mo, Zr, Y, Cs and Sr were below 5%. Therefore, Np and U could be effectively co-separated from the simulated HLW solution by controlling the oxidation state of Np.
Keywords:Neptunium;Oxieation/Reduction;Tributyl Phosphate;Solvent Extraction
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