Plutonium volatility in ozonization of alkaline solutions of Pu(VI) hydroxo complexes

Abstract

69 Processes involving the transition of chemical compounds into the gas phase are of both theoretical and practical significance. Such processes are impor� tant for actinides because their concentration, isola� tion, and purification and also isotope separation are known to present serious difficulties. Such processes are also important for plutonium. Assuming that the properties of the previously described plutonium tetroxide [1, 2] can be analogous to those of easily sub� limable osmium and ruthenium tetroxides and taking into account that both RuO 4 and OsO 4 can sublime even on weak heating from alkaline media, we tested the hypothesis of PuO4 volatility from alkaline solu� tions containing Pu(VIII). The existence of Pu(VIII) complexes (although of unknown composition) in a mixture with Pu(VII) complexes was postulated for the first time in [3–6], where it was assumed that Pu(VIII) derivatives can form under the action of an ozone–oxygen mixture on alkaline solutions of Pu(VI) complexes. This is also indicated by the corresponding spectral characteristics of Pu(VIII) and Pu(VII) complexes [7]. The extrac� tion of presumably PuO4 [1] from ozonated solutions suggests that they are characterized by a complex sys� tem of equilibria and contain both Pu(VII) and Pu(VIII) complexes and the said binary oxide. Thus, in an alkaline solution, there is likely a complex–tet� raoxide dynamic equilibrium, which can shift under the action of suitable extractants [1] and, furthermore, on heating. A similar equilibrium can also be assumed