SEPARATION OF U(Ⅳ)FROM U(Ⅵ)AND U(Ⅵ) FROM Th BY DIBENZO-18-CROWN-6 EXTRACTION CHROMATOGRAPHY

The adsorption coefficients of U(Ⅳ) and U(Ⅵ) between dibenzo-18-crown-6(DBC)-401 organic carrier powder and hydrochloric acid are measured in batch experiments. The effects of the concentration of DBC in the stationary phase and the concentration of hydrochloric acid and alkali cations in the aqueous phase on the adsorption coefficient of uranium are similar to the liquid-liquid extraction in the DBC-hydrochloric acid system. When a small amount of potassium is added to hydrochloric acid, the adsorption of uranium increases greatly.The separation of U(Ⅳ) from U(Ⅵ) and the separation of micro amount U(Ⅴ) from Th by DBC extraction chromatography is satisfactory.