Solubility Product of Hexavalent Uranium Hydrous Oxide

Uranium extraction from laboratory-synthesized, uranium-doped hydrous ferric oxides.

The extractability of uranium (U) from synthetic uranium-hydrous ferric oxide (HFO) coprecipitates has been shown to decrease as a function of mineral ripening, consistent with the hypothesis that the ripening process will decrease uranium lability. To evaluate this process, three HFO suspensions were coprecipitated with uranyl (UO2(2+)) and maintained at pH 7.0 +/- 0.1. Uranyl was added to the...

Solubility characterization of airborne uranium from a uranium recycling plant.

Solubility profiles of uranium dusts in a uranium recycling plant were determined by performing in vitro solubility tests on breathing zone air samples conducted in all process areas of the processing plant. The recycling plant produces high density shields, closed end tubes that are punched and formed from uranium sheet metal, and high-fired uranium oxide, which is used as a catalyst. The recy...

Microbial populations stimulated for hexavalent uranium reduction in uranium mine sediment.

Uranium-contaminated sediment and water collected from an inactive uranium mine were incubated anaerobically with organic substrates. Stimulated microbial populations removed U almost entirely from solution within 1 month. X-ray absorption near-edge structure analysis showed that U(VI) was reduced to U(IV) during the incubation. Observations by transmission electron microscopy, selected area di...

Multiple influences of nitrate on uranium solubility during bioremediation of uranium-contaminated subsurface sediments.

Microbiological reduction of soluble U(VI) to insoluble U(IV) has been proposed as a remediation strategy for uranium-contaminated groundwater. Nitrate is a common co-contaminant with uranium. Nitrate inhibited U(VI) reduction in acetate-amended aquifer sediments collected from a uranium-contaminated site in New Mexico. Once nitrate was depleted, both U(VI) and Fe(III) were reduced concurrently...

Uranium Ion Yields from Monodisperse Uranium Oxide Particles.