ABSTRACT
From the early 1960s, the methods for separating nuclear fission products were studied
at NRI, Rˇezˇ. For this purpose, the reagents formerly proposed for the precipitation of
cesium-like dipicrylaminate and tetraphenylborate-were successfully applied as
extractants for this fission product in the pioneering studies of Kyrs et al. [1] and Krtil
et al. [2] and the development of the extraction research followed. It was a challenging task at those times to find new extractants for cesium and various hydrophobic anions
were proposed. To enumerate just several of them, extraction with phosphomolybdic
acid anion was studied [3,4] and the mechanism of the extraction with picrate and
dinitrophenolate anions was elucidated [5]. As new hydrophobic anions, complexes of
As(V) with catechol or substituted catechols were proposed for extraction separation
of cesium [6-8]. The previously studied hydrophobic anions were subsequently largely
superseded by cobalt bis(dicarbollide) anions. The extraction with them was at first
reported in 1976 [9] and from that time a large body of material accumulated which is reviewed in Chapter 5 of this volume [10].
