Crystallography and mineralogy of supergene weathering products of uraninite at the nanoscale (UNanoCryst)


Uranium, as U(IV), undergoes transformation to U(VI) readily while exposed to oxidizing conditions. Generally, U(VI) occurs as the uranyl ion, UO22+. Its is highly mobile in aqueous solutions and can precipitate in natural conditions as uranyl minerals, the most oxidized forms of U that are common on the Earth surface or at near-surface conditions; as the result of oxidation weathering of uraninite, UO2. Their properties (such as, for instance, solubility) are key-factors for release, retention and distribution of U in the Environment. The goal of this project is to close the gap in our knowledge of properties of nanocrystalline uranyl carbonates and sulfates that are environmentally important, i.e. they precipitate frequently from aqueous solution on many contamined sites and localities worldwide.