The importance of the extraction medium and its film geometry to the separation efficiency is illustrated by the example of
the chromatographic extraction systems HDEHP-HCl-Eu3+ and TBP-HNO3−Sc3+. Starting from the geometry of the matrix, the effects of the exchange kinetics and flow pattern were experimentally proved.
Exchange kinetics are described as a heterogeneous transport-limited reaction in the aqueous phase. Four ranges of the rate
of exchange with the geometry of the matrix (pore diameter) were found. The flow patterns in the chromatographic layer can
be established by the individual pore cross-sectional area of the matrix. The sum of the effects of exchange kinetics and
flow patterns determines the chromatographic efficiency of the systems. Their relative effects in the two systems being investigated
In the course of ion-exchange separations of highly active solutions, the radiolysis gives rise to considerable disturbances
and deteriorated separation results. On the example of241Am/242Cm separations some results of radiolysis investigations for Dowex 50X8 are briefly shown, and experiences with the choice
of parameters of a high-pressure column system are described for several examples.
Authors:R. Henkelmann, A. Huber, S. Specht, and H. Stark
The analytical use of the prompt gamma-rays originating from neutron capture is a valuable completition of the conventional
neutron activation analysis. The application of the external radiation tube P2 of the research reactor in Munich, an Am—Be
neutron source of 300 mCi and a 1 mg252Cf neutron source is discussed.