1. Uranium speciation in two Freital mne tailing samples: EXAFS, micro- XRD and micro-XRF results.
- Author
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Scheinost A.C., Fourth Uranium mining and hydrogeology conference, UMH IV, Hennig C., Knappik R., Martinez-Criado G., Somogyi A., Scheinost A.C., Fourth Uranium mining and hydrogeology conference, UMH IV, Hennig C., Knappik R., Martinez-Criado G., and Somogyi A.
- Abstract
The German tailings investigated had been buried for 30 years under mine and construction debris. Selective sequential chemical extractions, bulk L(III)-edge X-ray absorption fine structure (EXAFS) spectroscopy and synchotron micro-X-ray fluorescence (XRF) and micro-X-ray diffraction (XRD) revealed two major U pools. The first, with a relatively high potential mobility, was identified as U(VI) sorbed to layer sillicates by inner-sphere complexing; the second was represented by the relatively insoluble U(IV) minerals pitchblende and coffinite, and by the U(VI) solids uranyl hydroxide and vanuralite. Distribution between the two pools seemed to be controlled by pH and evidence was found for reductive precipitation of uraninite., The German tailings investigated had been buried for 30 years under mine and construction debris. Selective sequential chemical extractions, bulk L(III)-edge X-ray absorption fine structure (EXAFS) spectroscopy and synchotron micro-X-ray fluorescence (XRF) and micro-X-ray diffraction (XRD) revealed two major U pools. The first, with a relatively high potential mobility, was identified as U(VI) sorbed to layer sillicates by inner-sphere complexing; the second was represented by the relatively insoluble U(IV) minerals pitchblende and coffinite, and by the U(VI) solids uranyl hydroxide and vanuralite. Distribution between the two pools seemed to be controlled by pH and evidence was found for reductive precipitation of uraninite.
- Published
- 2006