Alligator Rivers analogue project. Uranium sorption. Final report - volume 13
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Date
1992
Journal Title
Journal ISSN
Volume Title
Publisher
Australian Nuclear Science and Technology Organisation
Abstract
In this volume, the results of studies of uranium sorption (adsorption and desorption) to both single, well-defined mineral phases, and to selected natural (Koongarra) substrates are reported. The single phases included the amorphous iron oxide ferrihydrite, crystalline silica and two naturally occurring kaolinites, KGa-1 and Nichika. The surface properties of these materials were rigorously defined, and adsorption studies were conducted over a range of solution pH, ionic strength, carbonate content, adsorbent and adsorbate concentrations, and in the presence of uranium complexants and (potentially) competing adsorbates (such as phosphate and fluoride). The results of these studies were modelled using the 'surface complexation' approach, with a diffuse layer description of the electrical double layer. The impacts of mineral phase transformations (specifically the aging of amorphous ferrihydrite to more crystalline forms) on the uptake and desorption of uranium are also reported. The amount of data obtained in this study, with a number of experimental parameters being varied over a wide range, has enabled more confidence to be placed in the modelling results. The derived model for ferrihydrite adequately accounts for the effect on U sorption of a number of parameters, most notably pH, pCO2 and total U present. Few (if any) of the models previously proposed are adequate in this respect. While the modelling of the data for the natural substrates is not as advanced, the U sorption data on the natural substrates show similar features to the U sorption on the model substrates. This suggests that the insights obtained in the modelling of the data for ferrihydrite will be valuable in deriving a model for the more complex natural substrates
Description
Keywords
Alpha spectra, Alpha spectroscopy, Chemical reaction kinetics, Computerized simulation, Equilibrium, Experimental data, Fluorides, Geochemistry, Iron hydrides, Kaolinite, Koongarra deposit, Natural analogue, pH Value, Phase transformations, Phosphates, Phosphorescence, Quartz, Separation processes, Sorption, Sorptive properties, Substrates, Surface properties, Uranium, Uranium ores, Uranyl carbonates, Actinide compounds, Actinides, Aluminium compounds, Silicates, Carbon compounds
Citation
Waite, T. D., Payne, T. E., Davis, J. A., & Sekine, K. (1992). Alligator Rivers analogue project. Uranium sorption. Final report - volume 13, Menai, Sydney, NSW, Australia: Australian Nuclear Science and Technology Organisation.