Solvent extraction of actinides and nitric acid by crown-ethers

For the first time solvent extraction of thorium nitrate, nitric acid is investigated and isotherm of uranyl nitrate extraction by crown-ethers (0,1 M in dichloroethane) is obtained. The following ethers have been used: dicyclohexyl-18-crown-6(E1), 18-crown-6(E2), dibenzo-18-crown-6(E3), di(tret-butylbenzo)-18-crown-6(E4), di(tret-amylbenzo)-18-crown-6(E5), di(octylbenzo)-18-crown-6-dion(E6) and diaz-18-crown-6-trion (E7). Crown-ethers extract HNO3 at acidity up to 4M at the level of neutral phosphorus organic compounds. At high acidity there is no saturation and high extraction is observed. By extractive power E7 corresponds to E3, dion E6-E1. Thorium extraction by the studied ethers is poor, it decreases in the E1 > E2 > E3 series. The extraction isotherm by one of basic ethers E1 has a saturation corresponding to the metal/ligand 1:2 ratio. When extracting uranyl nitrate complexes of the 1:1 composition are formed. The de-- pendence of the distribution coefficient of Pu(4) and Np(4) on acidity is shown. Am extraction by crown-ethers turned to be poor