N,N-Dihexyl Hexanamide: A Promising Extractant for Nuclear Fuel Reprocessing
N,N-Dihexyl Hexanamide: A Promising Extractant for Nuclear Fuel Reprocessing
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N,N-二己基己酰胺：一种有前途的核燃料后处理萃取剂
DOI：
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发表时间：
2000
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影响因子：
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通讯作者：
R. Singh
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文献类型：
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作者：
K. Gupta;V. Manchanda;M. S. Subramanian;R. Singh
N，N-二烷基酰胺引起了从事开发磷酸三丁酯（TBP）替代萃取剂的放射化学家的注意，这些萃取剂用于后处理辐照燃料，特别是具有高辐射场和高钚含量的燃料。二己基己酰胺（DHHA）已被发现是一个很有前途的萃取剂在这个方向。萃取UO_2（NO_3）_2·2DHHA和Pu（NO_3）_4·2DHHA的Log K_（ex）值分别为1.43和3.62。在高硝酸浓度（5 M）下，酰胺发生质子化，并以（UO 2（NO3）3 −）（HDHHA+）和（Pu（NO3）6 2−）（HDHHA+）2型离子对形式萃取U（VI）和Pu（IV）。在痕量级浓度下，Pu（IV）和U（VI）与1 M DHHA的正十二烷溶液在3.5 M HNO 3下的分配系数（D）分别为41.2和13.5。同样，在有机相的铀饱和度为50%时，Pu（IV）和U（VI）的D值分别为9.2和4.2。这些结果表明，DHHA在改善钚的提取和铀的易剥离性方面优于TBP。0.5 M DHHA在30 Mrad下的分离因子分别为1.37（U/Zr）和1.75（Pu/Zr），表明与TBP相比，该萃取剂对辐照溶液中Pu和U的选择性特别有前途。在这项工作中获得的结果表明，酰胺在满足所带来的挑战的潜力大钚含量和高辐射领域的钚基燃料的后处理过程中遇到的排放热以及快功率反应堆。
N,N-Dialkyl amides have drawn the attention of radiochemists engaged in the development of alternate extractants to tri-n-butyl phosphate (TBP) for the reprocessing of irradiated fuels, particularly with high radiation fields and high plutonium content. Dihexyl hexanamide (DHHA) has been found to be a promising extractant in this direction. Log K ex values for the extraction of UO2(NO3)2·2DHHA and Pu(NO3)4·2DHHA in n-dodecane were found to be 1.43 and 3.62, respectively. At high nitric acid concentration (5 M), the amide undergoes protonation and extracts U(VI) and Pu(IV) as ion pairs of the type (UO2(NO3)3 −)(HDHHA+) and (Pu(NO3)6 2−)(HDHHA+)2. At trace level concentrations, the distribution coefficient (D) of Pu(IV) and U(VI) with a 1 M solution of DHHA in n-dodecane at 3.5 M HNO3 are 41.2 and 13.5, respectively. Similarly, at 50% uranium saturation of the organic phase the D values of Pu(IV) and U(VI) are 9.2 and 4.2, respectively. These results suggest the distinct advantages of DHHA over TBP in improved extraction of Pu and ease of stripping of uranium. The separation factors for 0.5 M DHHA at 30 Mrad are obtained as ∼37 (U/Zr) and ∼75 (Pu/Zr), suggesting that this extractant is particularly promising for the selectivity of Pu and U over Zr from irradiated solutions as compared to TBP. Results obtained during this work demonstrate the potential of amides in meeting the challenges posed by the large Pu content and high radiation fields encountered during the reprocessing of Pu-based fuels discharged from thermal as well as fast power reactors.