A Gas Sorption-Desorption Method for Recovering Plutonium Hexafluoride

In the search for an efficient sorption-desorption system for recovering and purifying plutonium hexafluoride, 31 candidate metal fluorides were tested. Of these, the fluorides of the IA and IIA metals were found to react (or sorb) most favorably and were therefore selected for further study. Results of extensive tests, in which the sorption and desorption capabilities of these more promising fluorides were considered, indicated that only lithium fluoride was effective in both respects. A chemical equilibrium was found to exist between plutonium hexafluoride, fluorine, lithium fluoride, and a complex (probably Li₄PuF₈) containing Pu(IV). The sorption of plutonium hexafluoride was much improved as the surface area of the lithium fluoride was increased. Plutonium hexafluoride containing no detectable uranium hexafluoride was obtained from a mixture by a sorption-desorption separation.