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Ren, Y.; Yang, X.; Hu, X.; Wei, J.; Tang, C. |
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Title |
Mineralogical and geochemical evidence for biogenic uranium mineralization in northern Songliao Basin, NE China |
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Journal Article |
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Year |
2022 |
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Ore Geology Reviews |
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141 |
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104556 |
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Keywords |
Bacterial sulfate reduction, In-situ S isotope of pyrite, Northern Songliao basin, Sandstone-type uranium deposit, Sifangtai Formation |
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Abstract |
The sandstone-hosted uranium mineralization areas in the Sanzhao Sag of the northern Songliao Basin have been newly identified. The target stratum is the Upper Cretaceous Sifangtai Formation and the uranium mineralization mainly occurs in the bottom of Sifangtai Formation, corresponding to channel sand bodies in meandering river system, characterized by medium to fine-grained sandstone. This study proposes the uranium metallogenic model through petrographic observation, whole rock geochemistry, mineralogical study of uranium occurrence form (SEM), organic matter rock–eval pyrolysis analysis (REP) and in-situ sulfur isotope determination of different generations of pyrite by LA-MC-ICP-MS. Compared with the sandstones collected in barren reduction and oxidization zones, the mineralized sandstones show obvious increase in the contents of TOC, total sulfur, Y and U. Petrographic observations indicate that organic matters are mainly inherited from land plants. REP data display that the organic matter (OM) disseminated in the sandstone has very low hydrogen index (HI) from around 0 to 21 mg HC/g TOC and varied oxygen index (OI) from 44 to 115 mg CO2/g TOC, corresponding to Type Ⅳ kerogen (degraded kerogen). There are two types of coffinite with different grain size, micro-particles (μm-sized) and large aggregates (generally up to 100 μm) respectively. The coffinite micro spherules exhibit short rod-like or worm-like morphology occurring in clay matrix and cell cavities in degradofusinite or around subidiomorphic-idiomorphic pyrite. The coarse-grained coffinite contains other mineral facies (e.g. pyrite, quartz) and some of large coffinite aggregates display thrombolite-type microbial structures. The irregular pyrite relict particles in coarse-grained colloidal coffinite have light sulfur isotope compositions characterized by δ34S values from –39.96‰ to –49.89‰. The δ34S values of colloidal pyrite in replacement of OM or of the sub-idiomorphic FeS2 cement filling in the cavities of OM range from –52.77‰ to –13.88‰. Some of sub-idiomorphic pyrite cement and idiomorphic crystal have the heavier signature from – 27.06‰ to + 14.23‰. The light sulfur isotope signature suggests that the sulfur originates from bacterial sulfate reduction (BSR). The OM replacement by pyrite and the highest OI values recorded by REP in uranium mineralized samples are lines of evidence of biodegradation. Bacteria use the organic matter as food source and produce isotopically light reduced sulfur species. Oxygenated uranium-bearing waters infiltrated through the denudated windows at Daqing placanticline into the porous reduced sandstones deposited in the Sanzhao Sag. Uranium was indirectly reduced by BSR-derived iron disulfides or directly reduced by sulfate-reducing bacteria. |
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0169-1368 |
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THL @ christoph.kuells @ ren_mineralogical_2022 |
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144 |
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French, K. |
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Indigenous knowledge, water management, and learning from our collective past |
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Journal Article |
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2022 |
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Journal of Anthropological Archaeology |
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68 |
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101466 |
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0278-4165 |
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THL @ christoph.kuells @ French2022101466 |
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253 |
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Zeng, S.; Shen, Y.; Sun, B.; Tan, K.; Zhang, S.; Ye, W. |
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Title |
Fractal kinetic characteristics of uranium leaching from low permeability uranium-bearing sandstone |
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Journal Article |
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2022 |
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Nuclear Engineering and Technology |
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54 |
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4 |
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1175-1184 |
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Fractal characteristics, In-situ leaching, Leaching kinetics, Pore structure, Uranium mine |
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The pore structure of uranium-bearing sandstone is one of the critical factors that affect the uranium leaching performance. In this article, uranium-bearing sandstone from the Yili Basin, Xinjiang, China, was taken as the research object. The fractal characteristics of the pore structure of the uranium-bearing sandstone were studied using mercury intrusion experiments and fractal theory, and the fractal dimension of the uranium-bearing sandstone was calculated. In addition, the effect of the fractal characteristics of the pore structure of the uranium-bearing sandstone on the uranium leaching kinetics was studied. Then, the kinetics was analyzed using a shrinking nuclear model, and it was determined that the rate of uranium leaching is mainly controlled by the diffusion reaction, and the dissolution rate constant (K) is linearly related to the pore specific surface fractal dimension (DS) and the pore volume fractal dimension (DV). Eventually, fractal kinetic models for predicting the in-situ leaching kinetics were established using the unreacted shrinking core model, and the linear relationship between the fractal dimension of the sample’s pore structure and the dissolution rate during the leaching was fitted. |
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1738-5733 |
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THL @ christoph.kuells @ zeng_fractal_2022 |
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193 |
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Sardo, M.S.; Jalalkamali, N. |
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A system dynamic approach for reservoir impact assessment on groundwater aquifer considering climate change scenario |
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Journal Article |
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2022 |
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Groundwater for Sustainable Development |
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17 |
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100754 |
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System dynamics, Water resources management, Vensim, Management scenarios |
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With its arid and semi-arid climate, Iran claims about one-third of the world’s average annual precipitation. Accordingly, the present study investigated whether an effective water resources management (WRM) strategy (both groundwater and reservoir resources) could reduce groundwater drawdown while simultaneously providing secure enough water for preservation of agricultural activities and rural settlements. For this purpose, a comprehensive system dynamics (SD) model incorporating reservoir, surface-water, and groundwater resources was developed. Then, the model was implemented for the Nesa plain in Bam County, Iran, as an example. In this plain, the construction of a dam to supply drinking water to the cities of Bam and the Bam Industrial Zone had devastated the environment and human communities in the downstream areas, leading to the depopulation of as many as 104 villages in the Bam region. The results of the SD model revealed that the artificial recharge of the plain groundwater aquifer along with the management of the operation of the wells and increasing productivity would be very effective. In order to estimate future precipitation data, the SDSM statistical exponential microscale model was used to microscale the large CanESM2 scale model under two scenarios of RCP4.5 and RCP8.5. The continuation of the current trend of the groundwater resources in the plain during the next 20 years will also cause a drop in water level of 8.3 m compared with the existing situation and a reduction of 41 m compared with the long-term average of 1980. Based on this modeling effort, upon releasing 60% of river flow, surplus to downstream demand, for recharging aquifer through artificial recharge projects, the rate of water table fall will decline significantly over a 20-year period and the amount of negative aquifer water balance would most likely improve from 65.5 to 35.17 million cubic meters annually. |
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2352-801x |
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THL @ christoph.kuells @ Shahrokhisardo2022100754 |
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266 |
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Aldawsari, S.; Kampmann, R.; Harnisch, J.; Rohde, C. |
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Title |
Setting Time, Microstructure, and Durability Properties of Low Calcium Fly Ash/Slag Geopolymer: A Review |
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Journal Article |
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2022 |
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Materials |
Abbreviated Journal |
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15 |
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3 |
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Ordinary Portland cement (OPC) is known for its significant contribution to carbon dioxide emissions. Geopolymer has a lower footprint in terms of CO2 emissions and has been considered as an alternative for OPC. A well-developed understanding of the use of fly-ash-based and slag-based geopolymers as separate systems has been reached in the literature, specifically regarding their mechanical properties. However, the microstructural and durability of the combined system after slag addition introduces more interactive gels and complex microstructural formations. The microstructural changes of complex blended systems contribute to significant advances in the durability of fly ash/slag geopolymers. In the present review, the setting time, microstructural properties (gel phase development, permeability properties, shrinkage behavior), and durability (chloride resistance, sulfate attack, and carbonatation), as discussed literature, are studied and summarized to simplify and draw conclusions. |
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1996-1944 |
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THL @ christoph.kuells @ ma15030876 |
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84 |
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