EXTRACTION OF URANIUM(VI) WITH A SERIES OF FIVE DCH(DICYCLOHEXYL) CROWN ETHERS IN HCI MEDIUM

This paper reports the extraction of UO_2Cl_2 by 26 crown ethers of differentstructure from HCl solution, with the emphasis on the following five crown ethers:DCH--28--C--6, DCH--21--C--7, DCH--24--C--8, DCH--27--C--9 and DCH--30--C--10 in the1,2--dichloroethane solution. Experimental results show that distribution coefficients(D) of U (VI) increase with the increase of HCl concentration, approach amaximum in 7 N HCl, and then sharply decrease. The stoichiometric ratio of U(VI)to crown ethers in the complexes is 1:2. When other conditions are the same, thedistribution coefficients in HCl medium are two orders of magnitude higher thanthose in HNO_3 medium. Extracted U (VI) can be completely stripped from theorganic phase by a single bed--extraction process with dilute acids or water.