Retention and redox behaviour of uranium(VI) by siderite (FeCO3)

In the context of long-term nuclear waste management, understanding the migration of a major component of spent fuel, uranium namely, in the environment is of major importance. This study presents the kinetics of uranium(VI) retention and reduction in carbonate solutions by siderite, an iron carbonate present both in the near- and far-field. At pH 9, uranium(VI) is retained at the surface, reduced and then precipitated into UO2.67. At pH 7, uranium(VI) seems, first, to be incorporated into iron precipitates at the solid/liquid interface and, subsequently, reduced by the Fe(II) contained in the thin layer. (orig.)