50 research outputs found
Incorporation of uranium into hematite during crystallization from ferrihydrite
Ferrihydrite was exposed to U(VI)-containing cement leachate (pH 10.5) and aged to induce crystallization of hematite. A combination of chemical extractions, TEM, and XAS techniques provided the first evidence that adsorbed U(VI) (≈3000 ppm) was incorporated into hematite during ferrihydrite aggregation and the early stages of crystallization, with continued uptake occurring during hematite ripening. Analysis of EXAFS and XANES data indicated that the U(VI) was incorporated into a distorted, octahedrally coordinated site replacing Fe(III). Fitting of the EXAFS showed the uranyl bonds lengthened from 1.81 to 1.87 Å, in contrast to previous studies that have suggested that the uranyl bond is lost altogether upon incorporation into hematite the results of this study both provide a new mechanistic understanding of uranium incorporation into hematite and define the nature of the bonding environment of uranium within the mineral structure. Immobilization of U(VI) by incorporation into hematite has clear and important implications for limiting uranium migration in natural and engineered environments. © 2014 American Chemical Society
In situ stable isotopic constraints on dolomitizing fluids for the hydrothermally-originated saddle dolomites at Keping, Tarim Basin
Detrital zircon U–Pb geochronology and provenance of the Neoproterozoic Lower Roan Group, Chambishi Basin, North‐eastern Zambia: Implication for rift evolution of the Congo Craton
Bacteria as indicators for finding oil and gas reservoirs: A case study of the Bikaner-Nagaur Basin, Rajasthan, India
The geology of the Mufulira deposit : implications for the metallogenesis of arenite‐hosted ore deposits in the Central African copperbelt
EVIDENCE FOR JETS FROM CALORIMETER EXPERIMENT E-609 AT FERMILAB ANL-Fermilab-Lehigh-Michigan-Pennsylvania-Rice-Wisconsin Collaboration
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