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本工作研究了硝酸体系中十六种不同结构的冠醚对铀(Ⅳ)的萃取,萃取性能以二环己基系列的冠醚为最好。溶剂的介电常数大时铀(Ⅳ)的分配比增加,非极性溶剂所得的分配比很小。铀(Ⅳ)的分配比随水相中硝酸浓度增大而增加,在6.5MHNO_3时分配比最大,然后分配比又随硝酸浓度的增大而降低。该冠醚体系的动力学性质很好且很容易解络。初步实验结果表明,UO_2(NO_3)_2与二环己基—18—冠—6的络合物组成为1:1。另外,该络合物的红外光谱特征与文献中所述铀(Ⅳ)的配位键合情况符合。
In this work, we studied the extraction of uranium (Ⅳ) with 16 different crown ethers of different structures in nitric acid system. The best extraction performance was crown ether of dicyclohexyl series. When the dielectric constant of the solvent is large, the distribution ratio of uranium (Ⅳ) increases, and the distribution ratio of the nonpolar solvent is small. The distribution ratio of uranium (Ⅳ) increases with the increase of nitric acid concentration in the aqueous phase, and the distribution ratio of uranium (Ⅳ) increases with the increase of nitric acid concentration at 6.5MHNO_3. The kinematic properties of the crown ether system are good and easily deintercalated. The preliminary experimental results show that the complex of UO_2 (NO_3) _2 and dicyclohexyl-18-crown-6 has a composition of 1: 1. In addition, the IR spectra of this complex are in agreement with the coordination bonding of uranium (Ⅳ) described in the literature.