Browsing by Author "Pepper, SE"

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    Application of chelating weak base resin Dowex M4195 to the recovery of uranium from mixed sulfate/chloride media
    (Elsevier, 2017-06-01) Ogden, MD; Moon, EM; Wilson, A; Pepper, SE
    The use of untreated seawater or bore water in uranium mineral processing circuits may represent a cheaper and more sustainable water resource for Australia’s mining operations. Using present technologies, the increased salinity from these water sources results in decreased uranium extraction and increased extraction of impurities. There is incentive to overcome these challenges, either through new technologies, or repurposing existing technologies. The ion exchange behaviour of U from sulfate media on the weakly basic chelating resin Dowex M4195 (bis-picolylamine functionality) and the effect of competing chloride and impurity metal ions (Th, Fe, Al, Cu, Ni) has been studied. Experiments to determine acid, and sulfate media behaviour, and extraction thermodynamics including the effect of increasing chloride concentration upon extraction behaviour were carried out. Dowex M4195 was found to have pK1 and pK2 values at 4.13 ± 0.04 and 2.1 ± 0.1 determined at 1.0 M NaCl. Dowex M4195 shows affinity for U(VI) over Fe3+ and Al3+ in sulfuric acid media with a U(VI) pH50 a full pH unit below that of Fe3+ at 0.17 and 1.82 respectively. With increasing chloride concentrations U and Th extraction is suppressed but Fe extraction increases. At the highest chloride concentrations explored Fe is preferentially extracted over U, and Th is not extracted at all. As chloride concentration increases the extraction of U passes through a minimum (40%) before increasing to around 60% for 4.0 M chloride at pH 1.80. Al3+ is not extracted by M4195 under any conditions explored. Dowex M4195 does show high selectivity for Cu and Ni over everything else. ©2017 Elsevier B.V
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    Corrigendum to “Application of chelating weak base resin Dowex M4195 to the recovery of uranium from mixed sulfate/chloride media” [Chem. Eng. J., 317 (2017) 80–89]
    (Elsevier, 2017-09-15) Ogden, MD; Moon, EM; Wilson. A; Griffith, CS; Mata, JP; Soldenhoff, KH; Pepper, SE
    The authors regret that the historical contributions from collaborators at ANSTO were not sufficiently acknowledged in this paper. The authors would like to add the following contributors, with the affiliations shown above. The acknowledgements should also state the following; “The authors would like to acknowledge the members of the Separations and Nuclear Chemical Engineering Research (SNUCER) group at the University of Sheffield who all assisted with this work in some capacity. Thank you to Prof. Neil Hyatt and Dr. Claire Corkhill in MIDAS, University of Sheffield for use of analytical equipment. Thank you to Dr. Gabriella Kakonyi at the Kroto Research Institute at the University of Sheffield for ICP-MS analysis. Funding was provided by the Department of Chemical and Biological Engineering at The University of Sheffield, as part of their start-up scheme. This work is published with the permission of the Australian Nuclear Science & Technology Organisation, where most of the work was conducted.” The authors would like to apologise for any inconvenience caused. © 2017 Elsevier B.V