Browsing by Author "Moon, EM"
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- ItemApplication 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, SEThe 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
- ItemCorrigendum 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, SEThe 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
- ItemDivergent Fe and S mineralization pathways during the oxidative transformation of greigite, Fe3S4(Elsevier, 2017-09-30) Moon, EM; Bush, RT; Gibbs, DHM; Mata, JPThe iron sulfide mineral greigite, Fe3S4, has previously been identified in the surface layers of the intertidal zone of a partially remediated acid sulfate soil wetland, representing an end-member in an iron sulfide mineralization pathway distinct from that of pyrite. The persistence of greigite is important for the stability of the remediated landscape, but the response of greigite to periods of oxygenation (for example, during a neap tide) is poorly understood. In this study, we employ X-ray absorption spectroscopy to identify the Fe and S speciation and mineralogy resulting from the oxidative disintegration of synthetic greigite under physiochemical solution conditions consistent with a partially remediated acid sulfate soil wetland. Results indicate divergent Fe and S mineralization pathways culminating in elemental sulfur and iron (hyr)oxide minerals. No sulfate-containing minerals were identified, and under all conditions tested, residual greigite remains. The oxidation products, and the presence of sulfur reducing bacteria, provide the right chemical environment for the reformation of greigite during the sub-oxic conditions of the rest of the tidal cycle. This likely explains the persistence of greigite in the intertidal zone, and implies that the oxidation of greigite is not detrimental to the long term stability of the acid sulfate soil remediation process. © 2017 Elsevier B.V.
- ItemImpact of chloride on uranium(VI) speciation in acidic sulfate ion exchange systems: towards seawater-tolerant mineral processing circuits(Elsevier, 2017-07-25) Moon, EM; Ogden, MD; Griffith, CS; Wilson, A; Mata, JPUsing X-ray absorption spectroscopy, we have identified the mechanism by which chloride impacts the extraction of U(VI) by a weak base anion exchange resin from acidic sulfate solutions. The amount of chloride present affects U(VI) speciation both in the feed solutions and adsorbed by the resin, and we find three distinct U(VI) species taken up by the resin across the salinity gradient, directly corresponding to changes in levels of U(VI) extraction. These findings are integral to the effective design of mineral processing circuits incorporating seawater—a cheaper and more sustainable water source than fresh water. © 2017 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V.
- ItemSelecting environmental water tracers to understand groundwater around mines: opportunities and limitations(Springer Nature, 2022-02-07) Kurukulasuriya, D; Howcroft, W; Moon, EM; Meredith, KT; Timms, WUnderground mining operations have the potential to alter groundwater systems and facilitate hydraulic connections between surface water and groundwater. The nature and degree of these interactions need to be evaluated to identify mining risks to surrounding water resources and to predict potential operational effects and environmental impacts, such as hydraulic stress on local surface waters. Environmental water tracers (EWTs) are commonly used to study such interactions in mine water and hydrogeological studies. However, the opportunities presented by EWTs could be more widely utilised to benefit the mining industry and the environment. Some of the challenges faced include the lack of practical frameworks, the need for more examples of EWTs applications in mining, and the possibility of complex interpretation of tracer results. This paper reviews previous studies that have applied EWTs in groundwater systems within or near mine sites, mostly from Australia, China, and India. The EWTs used in these studies include water quality parameters, major ions, stable isotopes, radioisotopes, and dissolved gases. The opportunities of applying multiple EWTs to identify water sources, mixing, and determine recharge rates and groundwater residence times are discussed. Limitations of different EWTs in terms of their capabilities, reliability, cost of analysis, effort, and processing times are reviewed. Steps for selecting suitable EWTs for specific mine hydrogeology assessments should be commensurate with the risks. Finally, this paper provides an overview of suitable EWTs that will be a useful contribution to appropriate water resource management decisions around mines. © 2022 The Author(s)
- ItemWater tracer technologies to detect sources of seepage and protect environmental assets(University of Wollongong/University of Southern Queensland, 2021-02-02) Timms, W; Kurukulasuriya, D; Howcroft, W; Moon, EM; Meredith, KTWater tracer technologies can help optimise water management in coal mining operations and improve outcomes from environmental studies and controls to protect sensitive assets. ACARP project C28024 (Stage 1) is demonstrating how tracer analysis of groundwater and surface water can provide information on whether systems are hydrologically disconnected, partly connected or well connected. This stage of the project is focusing on conventional tracers that are often used by other mining industries around the world (e.g. iron ore, potash) and in groundwater resource studies. Stage 2 of this project proposes to test new artificial tracers combined with suitable conventional tracers that are particularly useful for identifying seepage sources for control actions. This paper will demonstrate and discuss the benefits and limitations of major groups of conventional tracers that are commonly measured naturally in water. These include: field parameters (e.g. electrical conductivity, temperature), major and trace ions (e.g. metals), stable isotopes of oxygen and hydrogen, industrial compounds (CFCs and SF6) and dissolved carbon isotopes (i.e. inorganic and organic forms). In addition, this paper will discuss radioisotope tracers (e.g. tritium, carbon-14 and radon-222), as robust and proven tools to help differentiate shallow and deep groundwater where there is a contrast in water residence time (groundwater ‘age’). These tracers can provide useful information on seepage, despite higher analysis costs and turn-around times for laboratory results. Key findings from demonstration mine sites show the importance of combining physical water measurements (e.g. water levels and pumping rates) with a suitable combination of water tracers, depending on the site specific issues or study questions. For example, artificial tracers that are added to water sources are most suitable for identifying seepage and rapid flow pathways that can be a risk to underground operations. However, common artificial tracers such as added salts and dye tracers can also raise community concerns, such as producing fluorescent green creeks. Novel artificial tracers are able to overcome these risks. For example, synthetic DNA with uniquely designed fingerprints can be released at different times and locations to identify the sources of water to excavations can then be controlled. Commensurate with the risks of the project, a combination of suitable tracer technologies of different types can increase the confidence in identifying water sources and flow rates underground. However, the costs, limitations and practical challenges of each proposed tracer should be considered in planning tracer studies. The outcomes of these ACARP projects will assist coal mining operators in deciding on the suitable combinations of tracers for different types of operational and environmental risks associated with underground mining, and show how tracer technologies can be used to check possible flow paths in conceptual and numerical models.