An Interfacial Barrier observed during Liquid–Liquid Extraction of Uranyl Nitrate

Abstract

EARLIER investigations on the transfer of solutes across liquid–liquid interfaces in a stirred cell^1,2 have been extended to a study of the transfer of uranyl nitrate, in both directions, between water and three solvents, dibutyl carbitol, methyl isobutylketone (hexone) and tributyl phosphate; the last-named was used as 20 per cent solutions in the inert diluents, ‘odourless kerosene’, benzene, and carbon tetrachloride. The same apparatus was used as previously described, the two phases, contained in the upper and lower compartments of the transfer cell, being stirred independently. An annular gap between the two compartments enabled the interface to be constrained to a fixed plane of known area. A rigorous study of the hydrodynamics of this transfer cell had already been made¹, so that it was possible to compute the diffusional resistances on each side of the interface for any stirring conditions. The stirring-rates used were sufficiently high for transfer to and from the interface to take place by eddy diffusion, molecular diffusion being negligible.