Energy and Mineral Resources for a Sustainable Future

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https://hdl.handle.net/10388/14354

As Saskatchewan and the world transition from fossil-fuel-based energy systems, innovative solutions are needed to meet energy needs in a sustainable manner that goes hand-in-hand with public policy development to ensure all communities receive equal access to affordable and secure energy sources.

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Nature and origin of dolomite-hosted Th-U-HREE mineralization in the Tethyan Metallogenic Belt, Biga Peninsula, Northwestern Türkiye
(ScienceDirect, 2025-05) Ayetullah, Tunc; She, Zhenbing; Zhu, Yuxiang; Cao, Kenan; Deevsalar, Reza; Feng, Yuzhou; Pan, Yuanming
The Biga Peninsula in northwestern Türkiye, a metallogenic province in the Tethyan Metallogenic Belt, hosts economically significant gold-copper deposits and thorium-uranium-rare earth elements (Th-U-REE) occurrences, including both light REE (LREE) and heavy REE (HREE) styles of mineralization. This contribution focuses on the nature and origins of Th-U-REE mineralization in the Arıklı district, Biga Peninsula, where three zones of Th-U-REE mineralization (A, B, and C) each extends only a few meters along faults in Cenozoic volcanic rocks. Zones A and C of U-Th-LREE mineralization are hosted by fluorapatite-sulfide-hematite and dolomite-fluorapatite assemblages and have U-Th-REE concentrations up to 1,152 ppm and 2,221 ppm, respectively, with fluorapatite as the principal U-Th-REE-bearing mineral. In contrast, Zone B of Th-U-HREE mineralization is hosted by a dolomite-dominant assemblage, with Th, U, and total HREE + Y concentrations up to 25,600 ppm, 4,100 ppm, and 3,535 ppm, respectively, with cheralite (CaTh(PO4)2) as the principal ore mineral. Four stages of dolomite have been identified in the main mineralization Zone B: fine to medium-crystalline dolomite (D1; anhedral), pervasive medium-grained dolomite (D2; subhedral to anhedral), dolomite rhombs (D3), and void-/vein-filling coarse-crystalline dolomite (D4). Two stages of void-/vein-filling cheralite coincide with dolomite D3 and D4. The first stage cheralite shows intense hydrothermal modification, resulting in a disturbed U-Th-Pb isotopic system. Secondary cheralite of minimal hydrothermal disturbance yielded 206Pb-238U age of 18.8 ± 1.6 Ma (2σ, MSWD = 1.3) and 208Pb-232Th age of 18.15 ± 0.08 Ma (2σ, MSWD = 2.3). Carbon and oxygen isotope compositions differ significantly from those of primary igneous carbonatites but are close to sedimentary rocks, indicating that all dolomites have a hydrothermal origin with sedimentary sources. These results collectively suggest that Early Miocene hydrothermal fluids most likely originated from mantle-derived alkaline magmatism and interacted with carbonate sedimentary rocks, facilitating the mobilization, enrichment, and precipitation of dolomite-hosted Th, U, and HREE mineralization in fault zones.
Technology adoption in the Canadian mining sector: A systematic scoping review
(ScienceDirect, 2025-04) Crabbe, Mackenzie; Leader, Joelena; Hall, Heather M.; Burdett, Matthew
As the Canadian mining sector adopts new technologies, such as autonomous vehicles and artificial intelligence, there is the potential to reshape the future of work and the development of mining in Canada, impacting surrounding communities and regions. However, knowledge identified in the literature about the current trends, drivers, and barriers for the adoption of emerging technologies in the Canadian mining sector is limited and presents a clear research gap. This article reports on the findings of a non-traditional systematic scoping review focused on understanding current trends in technology adoption. More specifically, our team reviewed articles in the Canadian Mining Journal, a trade journal specific to our study area, to assess the main drivers, barriers, and opportunities for technology adoption in the Canadian context. Through this research, we have discovered that multiple drivers exist in the adoption of new technologies such as to increase productivity/efficiency, improve worker health and safety, and to increase sustainability. Although barriers were not as explicit, there were also concrete challenges to adopting new technologies identified such as mining culture and attitudes, technology and infrastructure challenges, and implementation challenges. Our research also highlights the need to adapt existing technology adoption theories to account for industry-specific factors such as the importance of health and safety. Additionally, this research provides insights for mining companies, technology providers, policymakers, and other stakeholders to develop strategies that support technology adoption and innovation in the mining sector.
Quantified growth and possible heterochronic development of two corynexochid trilobites from the middle Cambrian (Miaolingian Series, Wuliuan Stage) Mount Cap Formation, eastern Mackenzie Mountains, northwestern Canada
(Cambridge University Press, 2024-10-21) Handkamer, Neal M.; Pratt, Brian R.
The ontogeny of two species of corynexochid trilobites from the middle Cambrian Mount Cap Formation of the eastern Mackenzie Mountains, northern Canada, is documented. Sahtuia carcajouensis (Dolichometopidae) and Mackenzieaspis parallelispinosa (Zacanthoididae) are both endemic to this formation and only known from one locality. They, along with several other corynexochid taxa, occur in a succession of mudstone with scattered carbonate interbeds, deposited in a weakly storm-agitated setting near the flank of a semi-enclosed basin. The ontogeny of both species is characterized by mainly normal cranidial development, but a unique distribution of segments in their thoraxes and pygidia. The number of trunk segments was typical for their respective families, whereas the final number of segments released into the thorax was reduced. This occurred in both species through timing modifications to segment release, indicating heterochrony. Sahtuia carcajouensis and Mackenzieaspis parallelispinosa are likely derived from two separate clades, and heterochrony probably arose separately but synchronously. The endemicity of both species probably reflects unique paleoecological conditions in this part of the basin. Preliminary results indicate that the fossil-bearing mudstone was deposited under well-oxygenated conditions that underwent high nutrient flux and possibly experienced varying salinity. These factors may have affected the organisms’ physiology, or perhaps provoked an adaptation to achieve early maturation.
Data-driven exploration of weak coordination microenvironment in solid-state electrolyte for safe and energy-dense batteries
(Springer Nature, 2025) Lao, Zhoujie; Tao, Kehao; Xiao, Xiao; Qu, Haotian; Wu, Xinru; Han, Zhiyuan; Gao, Runhua; Wang, Jian; Wu, Xian; Chen, An; Shi, Lei; Chang, Chengshuai; Song, Yanze; Wang, Xiangyu; Li, Jinjin; Zhu, Yanfei; Zhou, Guangmin
The unsatisfactory ionic conductivity of solid polymer electrolytes hinders their practical use as substitutes for liquid electrolytes to address safety concerns. Although various plasticizers have been introduced to improve lithium-ion conduction kinetics, the lack of microenvironment understanding impedes the rational design of high-performance polymer electrolytes. Here, we design a class of Hofmann complexes that offer continuous two-dimensional lithium-ion conduction channels with functional ligands, creating highly conductive electrolytes. Assisting with unsupervised learning, we use Climbing Image-Nudged Elastic Band simulations to screen lithium-ion conductors and screen out five potential candidates that elucidate the impact of lithium coordination environment on conduction behavior. By adjusting the covalency competition between Metal−O and Li−O bonds within Hofmann complexes, we can manipulate weak coordination environment of lithium-ion for rapid conduction kinetics. Li | |sulfurized polyacrylonitrile (SPAN) cell using solid-state polymer electrolytes with predicted Co(dimethylformamide)2Ni(CN)4 delivers an initial discharge capacity of 1264 mAh g−1 with a capacity retention of 65% after 500 cycles at 0.2 C (335 mA g−1), at 30 °C ± 3 °C. The assembled 0.6 Ah Li | |SPAN pouch cell delivers an areal discharge capacity of 3.8 mAh cm−2 at the second cycle with a solid electrolyte areal mass loading of 18.6 mg cm−2 (mass-to-capacity ratio of 4.9).
Enhancing drying efficiency and terpene retention of cannabis using cold plasma pretreatment
(Elsevier, 2025-02-11) Das, Pabitra Chandra; Heydari, Mohamad Mehdi; Baik, Oon-Doo; Zhang, Lifeng; Tabil, Lope
Hang-drying of cannabis at room conditions is a slow process and leads to the risk of microbial growth. This method can sometimes prevent cannabis from reaching the equilibrium moisture content (EMC) below the safe storage threshold. On the other hand, high-temperature drying techniques are faster but negatively impact the secondary metabolites. Cold plasma (CP) is a novel technique explored in this study to treat cannabis at various operational conditions of plasma jet (power: 300, 350, and 400 W, time: 20, 30, and 40 s) prior to drying at environmental conditions of 25°C and 50 % RH. The findings revealed that untreated cannabis samples reached an equilibrium moisture content (EMC) of approximately 16 % in 1260 min. In contrast, CP-pretreated samples achieved lower EMCs of 10–14 % within 690–840 min. CP pretreatment also resulted in high moisture diffusivity, lower energy consumption, and higher energy efficiency. Increasing CP power and residence time accelerated the decarboxylation of cannabinoids, leading to the formation of more tetrahydrocannabinol (THC) and less tetrahydrocannabinolic acid (THCA), without significantly affecting the total THC (27.45 % untreated vs. 25.82 % - 28.36 % g/ g of dry matter in CP pretreated samples). Compared with untreated dried inflorescences, the 400 W and 30 s CP treated inflorescences resulted in the retention of 96 % of terpenes, whereas all 300 W CP treated samples retained > 90 % of terpenes. Overall, the study highlights that CP pretreatment is a promising technology for the cannabis industry in shortening the drying time and preserving the product quality, especially terpenes.
A methodology for selection of solid desiccants in energy recovery ventilators
(Elsevier, 2025-01-15) Krishnan, Easwaran N.; Ramin, Hadi; Gurubalan, A.; Muneeshwaran, M.; Li, Kai; Nawaz, Kashif; Simonson, Carey
Controlling indoor humidity levels is essential for maintaining acceptable indoor air quality in buildings. The use of energy recovery ventilators (ERVs) is an energy-efficient way to regulate indoor air humidity. Fixed-bed regenerators and rotary wheels are widely used ERVs because of their high sensible and latent effectiveness. These ERVs are made of desiccant-coated substrates, which enable them to transfer moisture between the supply and exhaust air streams. However, the moisture transfer ability of ERVs depends on the physiochemical and sorption properties of desiccants. Extensive, full-scale experiments are required to determine the best desiccant material for these systems. This paper presents a simplified method of selecting suitable desiccant materials for ERVs. The methodology involves important characterization methods, literature correlations for performance prediction, and cost-effective testing methods prior to full-scale testing, and full-scale test methods are discussed in detail. Furthermore, the performance of a few newly derived materials is evaluated and compared with that of conventional desiccants such as silica gel and molecular sieves. The highest latent effectiveness was obtained for composite of super absorbent polymer (SAP) with potassium formate (SAP-HCO2K-50 %), all-polymer porous solid desiccant (APPSD) and metal organic framework (MOF)–MIL–101 (Cr), followed by activated carbon fibre felt (ACFF) Silica sol-LiCl30, SAP, silica gel, MOF–303, and molecular sieve. Researchers and manufacturers would benefit from the proposed methodology and presented data in developing new desiccant materials for ERV applications.
Modeling a realistic integrated energy hub with growing demand for electric vehicles: The case of the province of Ontario, Canada
(Elsevier, 2025-01-28) Siroos, Ahmad; Samarghandi, Hamed
Energy hubs are multi-carrier energy management systems that efficiently distribute various forms of energy, reducing losses and environmental pollution. This paper examines Ontario, Canada, as a major energy hub, using a typical fall day pattern for energy demand. The model includes all power generation sources in Ontario: photovoltaic (PV), wind turbine (WT), nuclear, hydro, biofuel, and natural gas power plants. It also integrates the charging and discharging of electric vehicles (EVs) within the energy distribution framework. Managing the intrinsic uncertainty of the parameters is crucial for efficient operation. This study employs probabilistic functions to account for the arrival and departure hours of EVs, controlled using the Conditional Value at Risk (CVaR) method. Three methods, Information Gap Decision Theory (IGDT) with risk-seeking and risk-averse behaviors, and robust optimization, address uncertainties such as wind and solar electricity production, energy prices, and electrical, heating, and cooling demands. We compare simulation results of three scheduling scenarios for optimal energy production and dispatch. The RS-IGDT method can lead to significant losses during peak hours due to fluctuations. The robust method incurs higher costs by planning for large deviations. The RA-IGDT method balances deviations without the pessimism of the robust method, making it the recommended approach.
High strain rate compressive behavior of laser powder bed fused Inconel-718
(Elsevier, 2024-12-31) Hasani, Navid; CHALASANI, DHARMENDRA; Alaghmandfard, Reza; Keshavarzan, Mohsen; Forooghi, Foroozan; sanjari, mehdi; Shalchi Amirkhiz, Babak; Janaki Ram, G.D.; Pirgazi, Hadi; Kestens, Leo; Odeshi, Akindele; Mohammadi, Mohsen
Inconel-718 (IN718) is extensively utilized in the aerospace industry, notably in applications such as aircraft engines, facing a constant risk of foreign object impact loadings. Limited studies exist on the dynamic behavior of IN718 under high strain rate loadings, crucial for addressing the challenges of elevated operational temperatures and impact risks in aircraft engines. The dynamic deformation behavior of IN718 samples processed by laser powder bed fusion (LPBF) was studied at varying strain rates. True stress-strain curves showed rapid flow stress increase and semi-serrated stress-strain curves due to strain hardening and thermal softening competition. AMS 5664 heat treatment borrowed from the aerospace materials specifications (AMS) for nickel alloys led to a 28 % increase in ultimate compressive strength (UCS) at high strain rates. The aging treatment led to precipitation of uniformly distributed strengthening γ" and γ′ phases. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) investigations revealed adiabatic shear band (ASB) formation during high strain-rate deformation, indicating local temperature rise. High-density dislocation networks and nanoscale γ" and γ′ precipitates enhanced IN718 strength by inhibiting dislocation motion. Electron backscatter diffraction (EBSD) analysis highlighted texture changes, and the impact of strain rate on grain size distribution was observed. Slip activity increased after heat treatment, influencing ductility. Analysis of twins, kernel average misorientation (KAM), low-angle grain boundaries (LAGBs), and high-angle grain boundaries (HAGBs) were performed to investigate their contribution to the strength properties. Fracture surface analysis at 5150 s 1 revealed a complex mechanism, with outer regions exhibiting ductile features and inner regions indicating shear fracture. The Chang-Asaro (CA) model predicted IN718 flow behavior under high strain rates, subsequently incorporated into ABAQUS Explicit software for numerical simulation. Lagrangian smoothed particle hydrodynamics (SPH) in combination with the VUHARD subroutine were employed to simulate the SHPB experiments. The constitutive model incorporated in the subroutine accurately captured the nonlinear behavior of the specimens, such as equivalent plastic strain and temperature. The results demonstrated a strong validation between the experimental and numerical methodologies.
Thickness of the stratigraphic record of Britain: How the fidelity of geological and fossil data is unrelated to rock quantity
(Earth-Science Reviews, 2025-01) Craig, James A.; Battle, Ralph J.; Veenma, Yorick P.; McMahon, William J.; Slater, Ben J.; Shillito, Anthony; Davies, Neil S.
The sedimentary-stratigraphic record is the principal repository of empirical historic evidence for evolution and deep time environments. However, the record has a temporal incompleteness and inconsistency to its extensive quantity, driven by the spatial heterogeneity of deposition and erosion. This is argued to bias intensive fossil records, with correlations apparent between fossil diversity and mapped rock area from different intervals. However, mapped rock area is a poor proxy for strata accessible for fossil studies because most is concealed. Additionally, spatially diminutive older rocks commonly sample a greater stratigraphic transect per unit exposure area than widespread younger rocks because the tectonic forces that drive recycling additionally result in tilting. We calculate observable vertical stratigraphic thickness throughout geologic history for southern Britain and show that potential sample availability increases with age, in contrast to general models of rock survivorship. Using this subsample of the sedimentary-stratigraphic record as a calibration sample for the global record, we find no correlation between available stratigraphic thickness and palaeobiodiversity, except in flat-lying strata. We demonstrate instances where the first occurrences of fossil genera appear robust because there is high availability of suitable host rock pre-dating them. Our work suggests that preservation biases induced by variability in rock quantity have been significantly overstated and that local tectonic history renders different regions as stratigraphic hotspots for specific intervals, in which intensive high-veracity fossil records have exceptional value for elucidating global trends and timing in evolutionary history. The British non-marine Palaeozoic record is highlighted as such an example, with high-fidelity palynological records of plant evolution and ichnological records of animal terrestrialization.
Time, space and synoptic topography: how to read outcrops as a granular record of Earth history
(Geological Society, London, Special Publications, 2025-01) Davies, Neil; Veenma, Yorick P.; Craig, James A.; Allport, Hamilton A.; McMahon, William J.; Shillito, Anthony
Siliciclastic strata commonly preserve chronostratigraphic surfaces that record the ancient interface of sediment and water/air, in the form of true substrates on bedding planes and sampled topography in stratigraphic profiles. Such surfaces are commonly a reflection of sedimentary stasis, a sedimentation state where neither deposition or erosion was occurring. Sedimentary stasis may be instantaneous, temporary or prolonged, and may also be considered to occur when the constituent grains of a substrate remain in motion as the surface active layer, when the elevation of the lithic surface does not change. The preservation of patches of synoptic topography requires only that sedimentation states of deposition, erosion and stasis fluctuate, but is more common in lower energy parts of a depositional environment. Certain sedimentary features associated with true substrates and sampled topography can, through modern analogy, be used to determine the likely duration of sedimentary stasis. Here we use original case studies to show how the duration of this stasis can be variable depending on facies and stratal age, but that at outcrop scale it is always a very short interval relative to the longevity of a depositional environment. With examples from several siliciclastic facies and geological periods, we show that stratigraphic time preserved at outcrop scale can be very short, indicating that the total stratigraphic record is built brick by brick of many lower hierarchy snapshots. This understanding shifts perspectives on the stratigraphic record as an archive, with implications for the meaning of sedimentary signatures at outcrop and the construction of narratives to understand Earth history.
Chronic radium-226 bioaccumulation and toxicity in the aquatic invertebrate Daphnia magna
(Springer, 2025-01-06) Lacroix-Durand, Charlotte; Janz, David; Liber, Karsten
Mining operations in Canada, including uranium mining and milling, generate by-products containing radionuclides, including radium-226 (226Ra), a long-lived, bioaccumulative calcium (Ca2+) analog. Despite strict discharge regulations, there is limited evidence to suggest that current thresholds for 226Ra adequately protect aquatic organisms. Furthermore, Canada lacks a federal water quality guideline for 226Ra, underscoring the need for protective limits to safeguard aquatic ecosystems. Hence, this research aimed to generate data on 226Ra toxicity to the model aquatic invertebrate Daphnia magna. For this purpose, two 21-day chronic toxicity tests with D. magna were conducted, with survival and reproduction as the endpoints, as well as a reduced water hardness experiment, a multigenerational study, and a bioaccumulation assay. These experiments demonstrated that a high activity concentration (nominal 50 Bq/L) of 226Ra can significantly impact the survival of D. magna. 226Ra was also found to bioaccumulate in D. magna with a BAF of 72.8. Since the Canadian Metal and Diamond Mining Effluent Regulations (MDMER) monthly mean effluent limit is currently set at 0.37 Bq 226Ra /L, the limit for composite samples at 0.74 Bq/L 226Ra, and the limit for grab samples at 1.11 Bq/L 226Ra, it is unlikely that toxic effects to aquatic cladocerans like D. magna from 226Ra will be observed downstream of Canadian mines and mills.
Chronic Radium-226 Toxicity to and Oxidative Stress in the Aquatic Invertebrate Chironomus dilutus
(Oxford University Press, 2025-01-12) Lacroix-Durand, Charlotte; Janz, David; Liber, Karsten
The mining industry, including uranium mining and milling, is of high importance in Canada. It is, however, important to consider that ore processing can result in the creation of by-products that contain radionuclides such as radium-226 (226Ra). Even with the strict discharge regulations in place, there is limited evidence to suggest that the current Canadian regulatory thresholds for 226Ra are protective for aquatic life. This concern underscores the importance of generating toxicity data for 226Ra, as no federal Canadian water quality guidelines for 226Ra currently exist to safeguard aquatic ecosystems. The potential ecological risks of 226Ra are significant due to its high mobility under typical environmental conditions, long half-life (t1/2 ~ 1,600 years), bioaccumulative properties, and similarity to calcium (Ca2+). Considering this, the primary objective of this research was to gather data on the toxicity of 226Ra to the aquatic invertebrate Chironomus dilutus. For this purpose, a partial life cycle experiment was conducted, with larval growth, survival and pupation, and emergence and sex ratio of emerged adults, as the experimental endpoints. In addition, an assessment of oxidative stress as a potential cause of toxicity was performed. These experiments revealed that elevated activity concentrations of 226Ra (25.5 Bq/L) can significantly impact the growth of C. dilutus. However, none of the other nonlethal endpoints were significantly affected by 226Ra exposure, and there was no evidence of oxidative stress in exposed C. dilutus. Finally, 226Ra was shown to adsorb onto the silica sand used as a substrate for all experiments and desorbed following acid extraction.
Exploring the significance of true substrates in a Pennsylvanian fluvio-estuarine tidal flat
(Geological Society Special Publications, 2025-01-25) Buatois, Luis; Mángano, M. Gabriela; Maples, Christopher G.
The Pennsylvanian Tonganoxie Sandstone of Kansas contains examples of true substrates in tidal rhythmites formed in a tidal flat at the fluvio-estuarine transition of a macrotidal valley. These surfaces are characterized by an impressive preservation of biogenic and physical sedimentary structures, indicative of the coexistence of low-energy tidal currents and freshwater conditions together with brief periods of subaerial exposure. Biogenic activity corresponds to a time of stasis during or immediately after accumulation of ebb-phase clay followed by low tide. Deposition-stasis-deposition (D-S-D) was involved in the formation and preservation of these true substrates, with only a few instances of deposition-stasis-erosiondeposition (D-S-E-D). Crosscutting relationships among biogenic structures and of these with physical sedimentary structures suggest a tidally controlled taphonomic pathway, which indicates that these true substrates represent short-term time-averaged surfaces at the scale of a few hours, rather than snapshots. True substrates preserved in tidal rhythmites are widespread in other late Palaeozoic tide-dominated estuarine deposits of the North American Midcontinent. The likelihood and quality of preservation seem to show spatial and temporal trends at various scales that ultimately reflect a complex interplay of abiotic factors (e.g. sedimentary dynamics) and biotic factors (e.g. secular changes in intensity and depth of bioturbation).
Trophic magnification rates of eighteen trace elements in freshwater food webs
(Science of The Total Environment, 2024-12) Pelletier, Alexander R.; Villamarin, Francisco; Campos-Silva, João V.; Scabin, Andressa B.; Doig, Lorne E.; Jardine, Timothy D.
Trace elements play diverse roles in animal physiology ranging from essential micronutrients to potent toxicants. Despite animals accumulating many trace elements through their diets, relationships between trophic positions and biological concentrations of most trace elements remain poorly described. We report trophic transfer rates of Al, As, Ba, Cd, Co, Cu, Fe, Hg, Mn, Ni, Pb, Se, Sr, Ti, Tl, U, V, and Zn from 31 freshwaters located in distinct biogeographic regions. Elemental concentrations and stable nitrogen isotope ratios (proxies for trophic position) were determined in zooplankton, molluscs, insects, and fishes from all sites. Trophic magnification factors (TMFs) were calculated as the mean fraction of each element that transferred from prey to predators at each site. TMFs >1 indicate biomagnification and TMFs <1 indicate biodilution. Mercury was the only biomagnifying element (median TMF = 3.77), and selenium neither biomagnified nor biodiluted (median TMF = 1.01). All 16 remaining elements biodiluted, with median TMFs ranging from 0.07 (uranium) to 0.60 (thallium). We used a model selection procedure to determine whether intrinsic physical and chemical elemental properties explained differences in TMFs among elements. Elements with high covalent bonding indices (Q) had marginally greater TMFs than elements with low Q values. Based on their high Q values, we recommend investigation into the trophic transfer rates of ten additional trace elements, some of which may biomagnify through some aquatic food webs. The high variability in TMFs within elements suggests that ecological factors are likely more important than intrinsic elemental properties at determining elemental TMFs.
Thorium speciation in titania slag: Implications for environmental remediation and valorisation
(Mineralogical Magazine, 2024-11) Chadirji-Martinez, K; Hudon, G; Chernikov, R; Heredia, E; Feng, Renfei; Crawford, A; Pan, Yuanming
Titania slag, produced from smelting placer ilmenite concentrates and used as a feedstock for TiO2 pigment production, contains low levels of radioactivity due to thorium and uranium. This study investigated the distribution and speciation of thorium in Rio Tinto Chloride Slag (RTCS), which contains an average of 170 ppm Th and 16 ppm U, using a variety of analytical methods from powder X-ray diffraction (pXRD) analysis to bulk and laser ablation inductively coupled plasma mass spectrometry (ICP-MS and LA-ICP-MS), electron microprobe analysis (EMPA), quantitative evaluation of materials by scanning electron microscopy (QEMSCAN), Raman spectroscopy, microbeam synchrotron X-ray fluorescence (µsXRF) mapping, synchrotron Laue X-ray diffraction (LXRD) and synchrotron X-ray absorption spectroscopy (XAS). Our data demonstrate that ~99.4% of Th in the RTCS is hosted by a chevkinite-like Th-REE-Ti aluminosilicate containing an average of 8.05±0.64 wt.% ThO2. The Th-REE-Ti aluminosilicate occurs as acicular (~0.3x12 µm) or tabular (~5x15 µm) crystals in association with a Th-bearing aluminosilicate glass (0.41±0.35 wt.% ThO2) as infillings either in interstitials or along the fractures of the main Ti-Fe oxides of the sassite-ferropseudobrookite solid-solution series. The Th-REE-Ti aluminosilicate and associated Th-bearing aluminosilicate glass formed probably during the quenching stage of the titania slag production. LA-ICP-MS analyses and µsXRF mapping show that the main Ti-Fe oxides in the RTCS contain only an average of 0.32±0.60ppm Th. Future pyrometallurgy operations that utilize Th- and U-bearing heavy mineral sands must consider their environmental effects and mitigate radioactivity. Also, preferential acid dissolution of the Th-REE-Ti aluminosilicate in RTCS and other titania slags may be used to recover Th and REE for dual environmental and economic benefits.
Exploring energy transition narratives through mayoral insights using artificial intelligence
(Elsevier, 2024-12-21) Ahmed, Fatma; Ahmed, Rwan; Poelzer, Greg; Poelzer, Gregory; Söderberg, Charlotta; Zapata, Oscar; Guilmette, Elaina
This paper explores energy transition dynamics in three Arctic cities: Luleå (Sweden), Fairbanks (Alaska), and Yellowknife (Canada), with a focus on sustainable urban development. Semi-structured interviews with the mayors of these cities provide insights into their decision-making processes and strategies regarding energy transitions. Using Natural Language Processing (NLP) for semantic analysis, the study uncovers implicit priorities, challenges, and aspirations from the qualitative data. The analysis is guided by the theory of planned behavior, which helps to explain the underlying motivations, attitudes, and perceived behavioral control that influence policy decisions. Results reveal common themes such as balancing environmental goals with economic and social concerns, while also highlighting context-specific challenges in each city. This research contributes to the understanding the role of municipal leadership in energy transitions and demonstrates the effectiveness of NLP techniques in extracting meaningful insights from interviews. The findings aim to inform policymakers and urban planners on fostering sustainable energy transitions in Arctic regions.
Highly Stabilized Ni-Rich Cathodes Enabled by Artificially Reversing Naturally-Formed Interface
(Advanced Energy Materials, 2024-11) Ma, Jinjin; Sun, Yipeng; Wu, Duojie; Wang, Changhong; Yu, Ruizhi; Duan, Hui; Zheng, Matthew; Ruying, Li; Danny Gu, M; Zhao, Yang; Zhou, Jigang; Sun, Xueliang
A significant obstacle in the manufacturing and practical application of Ni-rich cathode materials is decreasing the manufacturing cost without sacrificing the cycling stability. Here a high-energy, ultrahigh-Ni, and nearly Co-free cathode with outstanding cycling performance is proposed. This promising cathode is enabled by artificially constructing an “outside-in” interface structure toward LiNi0.94Co0.05Mn0.01O2 (NCM94) cathodes. Combining theoretical prediction and experimental results, it is revealed that high interfacial stability is achieved by a specific surface chemistry with an outside-in structure composed of an inner organic layer and an outer inorganic layer. Benefiting from the protection effect of the robust outside layer and the strain relieve function of the inside layer, the intrinsic challenges of interfacial reactions, transition metal (TM) dissolution, and micro-crack propagation have been mitigated for the Ni-rich cathode. As a result, the “outside-in” strategy enables superior cycling stability with a 92.7% retention after 200 cycles and an excellent rate capability of 149.1 mAh g−1 at 10 C, achieved by adding only 0.5% of the production cost. This study unlocks the possibilities of achieving outstanding performance for ultrahigh Ni cathode by spending minimum cost through the facile surface chemistry method.
Stabilization of Oil-in-Water Pickering Emulsions by Surface-Functionalized Cellulose Hydrogel
(Gels, 2024-10) Udoetok, Inimfon; Mohamed, Mohamed H.; Wilson, Lee
An amphiphilic cellulose (CLH) hydrogel was synthesized via grafting of quaternary ammonium groups onto cellulose. The structural properties of CLH were characterized via Fourier transform infrared (FTIR)/13C solid-state NMR spectroscopy, elemental (CHN) analysis, particle size distribution (PSD), thermogravimetric analysis (TGA), and wettability was assessed through contact angle measurements. Pickering emulsions of apolar oils in water were prepared using variable weights of the CLH hydrogel as the stabilizing agent, along with different methods of agitation (mechanical shaking and sonication). The characterization results for CLH provide support for the successful grafting of quaternary ammonium groups onto cellulose to produce hydrogels. Different methods of agitation of an oil/water mixture revealed the formation of an oil-in-water (O/W) Pickering emulsion that was stable to coalescence for over 14 days. The resulting emulsions showed variable droplet sizes and stability according to the dosage of CLH in the emulsion and the agitation method, where the emulsion droplet size is related to the particle size of CLH. The addition of methyl orange (MO), a probe to evaluate the phase partitioning of the dye, had minor effects on the emulsion droplet size, and the emulsion prepared with 0.8 wt.% of CLH and agitated via sonication exhibited the smallest droplet size and greatest stability. This study is anticipated to catalyze further research and the development of low-cost and sustainable biopolymer hydrogels as stabilizers for tunable Pickering emulsion. Grafted cellulose materials of this type represent versatile stabilizing agents for foods, agrochemicals, and pharmaceutical products and technologies.
Hybrid Chitosan Biosorbents: Tunable Adsorption at Surface and Micropore Domains
(Biomimetics, 2024-11) Udoetok, Inimfon; Mohamed, Mohamed H.; Wilson, Lee
Herein, we report a study that provides new insight on the knowledge gaps that relate to the role of biopolymer structure and adsorption properties for chitosan adsorbents that are cross-linked with glutaraldehyde. The systematic modification of chitosan cross-linked with glutaraldehyde (CG) and its quaternized forms (QCG) was studied in relation to the reaction conditions: mole ratios of reactants and pH conditions. Complementary adsorbent characterization employed 13C NMR/FTIR spectroscopy, TGA and DSC, point-zero-charge (PZC), solvent swelling, and sorption studies using selected dye probes. The spectral and thermal techniques provide complementary evidence that affirm the key role of cross-linker content and quaternization on variation of the physicochemical properties of chitosan. The PZC results reveal a neutral surface charge for the modified materials between pH 6.0 to 6.3 ± 0.3, as compared with pH 8.7 ± 0.4 for pristine chitosan. Solvent swelling in water decreased with greater cross-linking, while the QCG materials had greater swelling over CG materials due to enhanced hydration. The adsorption results reveal variable dye uptake properties according to the cross-linker content. Similarly, surface versus micropore adsorption was demonstrated, according to the nature and ionization state of the dye for the modified adsorbents, where the CG and QCG materials had tunable sorption properties that exceeded that of unmodified chitosan. A key step in tuning the structure and surface chemical properties of cross-linked chitosan involves pH control during synthesis. The facile tunability of the physicochemical properties of the modified biopolymers reported herein means that they possess features of biomimetics that are relevant to advanced drug delivery, antimicrobial materials for wound healing, biosensors, and biosorbents for biomedical applications.
Reactive transport modelling of porewater geochemistry and sulfur isotope fractionation in organic carbon amended mine tailings
(Elsevier, 2021-04-01) Craig, Andrew T.; Shkarupin, Alexi; Amos, Richard T.; Lindsay, Matthew B. J.; Blowes, David; Ptacek, Carol
Field experiments previously conducted to assess organic carbon (OC) amendments for in situ biological treatment of tailings porewater at the Greens Creek Mine (Alaska, USA) showed SO4 reduction, metal-sulfide precipitation, and decreased fluxes of SO4 and dissolved metals. Here, we develop two reactive transport models using the reactive transport code MIN3P to simulate hydrogeochemical processes and δ34S-SO4 isotope fractionation over four years in test cells containing unamended (control) and amended (5 vol. % OC) tailings. These models successfully simulate observed data including pH, SO4, δ34S-SO4, Ca, Fe, K, Mg, Mn, Si, and Zn. The models also indicate that dissolution of carbonate and, to a lesser extent, aluminosilicate minerals neutralize acidic porewater generated from sulfide mineral oxidation and SO4 reduction reactions. Application of a constant kinetic fractionation factor of 0.9820 to simulate measured δ34S-SO4 trends confirms that SO4 removal principally results from microbially-mediated SO4 reduction in conjunction with OC oxidation and subsequent metal-sulfide precipitation. Gypsum precipitation/dissolution and thiosulfate disproportionation have negligible effects on modelled porewater δ34S-SO4 signatures. Our simulations are consistent with the previous findings that metal-sulfide precipitation controls Fe and Zn attenuation in amended tailings and that coprecipitation reactions contribute to metal removal. Overall, these simulations demonstrate that coupled reactive transport modelling incorporating stable isotope fractionation can improve the understanding of hydrogeochemical and biogeochemical controls within in situ treatment systems, further illustrating the benefits and limitations of this technique for improving water quality of mine drainage.

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