Quantifying the impact of mineralogical heterogeneity on reactive transport modeling of CO2 + O2 in-situ leaching of uranium

Yang, Yun; Qiu, Wenjie; Liu, Zhengbang; Song, Jian; Wu, Jianfeng; Dou, Zhi; Wang, Jinguo

doi:10.1007/s11631-021-00502-1

Cited by 11 publications

(8 citation statements)

References 31 publications

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“…It indicates that pyrite oxidation and U(IV) oxidation were mainly controlled by thermodynamics in the presence of dissolved O 2 . Although the ∆G value of NH 4 + oxidation was comparable to that of U oxidation, the O 2 ‐consumption by NH 4 + oxidation (2.6%) was significantly lower than that by U oxidation (39.3%), which might be attributed to the relatively lower content of NH 4 + than U content in ore‐bearing aquifer with high density (2,300 kg/m 3 ) and low porosity (0.25%) (Yang et al., 2022). Additionally, in spite of a more negative ∆G value of DOC oxidation than that of U oxidation, O 2 consumption of DOC oxidation was much lower (1.9%).…”

Section: Discussionmentioning

confidence: 92%

“…In situ leaching (ISL) is the main leaching method for sandstone‐type uranium ore (Abzalov, 2012; Mudd, 2001a, 2001b), mainly including acidic (Su et al., 2020; Zhou et al., 2020), neutral (Yang et al., 2022), and alkaline ISL (Abzalov, 2012). The neutral ISL (i.e., CO 2 + O 2 ISL) minimizes groundwater pollution during leaching and is considered to be more environmentally friendly (Yang et al., 2022; K. Zhao et al., 2022; Y. Zhao et al., 2022). As the inverse process of U mineralization, the injection of dissolved CO 2 and O 2 in the CO 2 + O 2 ISL substantially increases the redox potential and concentration of dissolved HCO 3 − , which oxidizes the reduced U(IV) to oxidized U(VI) and stimulates complexation of U with bicarbonate, including uranyl dicarbonate [UO 2 (CO 3 ) 2 2− ], uranyl tricarbonate [UO 2 (CO 3 ) 3 4− ], and ternary Ca/Mg‐UO 2 ‐CO 3 complexes (Su et al., 2020; Yang et al., 2022).…”

Section: Introductionmentioning

confidence: 99%

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Multi‐Isotope Based Identification and Quantification of Oxygen Consuming Processes in Uranium Hosting Aquifers With CO₂ + O₂ In Situ Leaching

Xiu

Guo

et al. 2023

Water Resources Research

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Although neutral in situ leaching through CO2 + O2 is employed to extract uranium (U) in sandstone by in situ leaching (ISL), mechanisms of U mobilization and O2 consumption remained unclear. To address this gap, 18 groundwater samples were taken from the Qianjiadian sandstone U ore field, including seven samples from production wells in mining area M1 (mining for 5 years), six samples from production wells in mining area M2 (mining for 4 years), and five samples from monitoring wells (GC), to quantify U‐mobilizing processes in the mining aquifer by employing hydrogeochemical compositions and multi‐isotopes. The introduction of O2 and CO2 efficiently stimulated U mobilization in the mining aquifer. The injected CO2 critically promoted the dissolution of carbonate minerals, which enhanced the formation of uranyl carbonate (predominantly CaUO2(CO3)22− and Ca2UO2(CO3)3(aq)) and thus facilitated U mobility. Generally, δ34SSO4 and δ18OSO4 in M2 and M1 were significantly lower than those in GC (p < 0.01). A Bayesian isotope mixing model of δ34SSO4 and δ18OSO4 showed that the contribution of pyrite oxidation to SO42− concentration increased from 1.7% in GC to 13.6% in M2 and to 15.0% in M1. During ISL, pyrite, ammonium, and dissolved organic carbon were major compounds competing with U(IV) for introduced O2 in the ore‐bearing aquifer. Most of the consumed O2 was used for pyrite oxidation (56.2%) and U(IV) oxidation (39.3%), following the thermodynamic sequence of those redox reactions. The current results highlighted the significance of increasing O2 utilization efficiency in improving the performance of ISL operations.

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Section: Discussionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Multi‐Isotope Based Identification and Quantification of Oxygen Consuming Processes in Uranium Hosting Aquifers With CO₂ + O₂ In Situ Leaching

Xiu

Guo

et al. 2023

Water Resources Research

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“…More details of RTM development are provided in the references of Yang et al (2022) and Qiu et al (2023).…”

Section: Reactive Transport Modelingmentioning

confidence: 99%

Assessment of the Greenhouse Gas Footprint and Environmental Impact of CO₂ and O₂ in situ Uranium Leaching

Yang

ZUO

Qiu

et al. 2023

Acta Geologica Sinica (Eng)

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Under the new development philosophy of carbon peaking and carbon neutrality, CO2 and O2 in situ leaching (ISL) has been identified as a promising technique for uranium mining in China, not only because it solves carbon dioxide utilization and sequestration, but it also alleviates the environmental burden. However, significant challenges exist in assessment of CO2 footprint and water‐rock interactions, due to complex geochemical processes. Herein this study conducts a three‐dimensional, multicomponent reactive transport model (RTM) of a field‐scale CO2 and O2 ISL process at a typical sandstone‐hosted uranium deposit in Songliao Basin, China. Numerical simulations are performed to provide new insight into quantitative interpretation of the greenhouse gas (CO2) footprint and environmental impact (SO42 –) of the CO2 and O2 ISL, considering the potential chemical reaction network for uranium recovery at the field scale. RTM results demonstrate that the fate of the CO2 could be summarized as injected CO2 dissolution, dissolved CO2 mineralization and storage of CO2 as a gas phase during the CO2 and O2 ISL process. Furthermore, compared to acid ISL, CO2 and O2 ISL has a potentially smaller environmental footprint, with 20% of SO42– concentration in the aquifer. The findings improve our fundamental understanding of carbon utilization in a long‐term CO2 and O2 ISL system and provide important environmental implications when considering complex geochemical processes.

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“…The Qianjiadian uranium deposit (Songliao Basin, northern China) has the characteristics of low average grade, large distribution area, considerable reserves, low cost of in situ leaching, and pollution-free, which is of great industrial value. As the only in situ leachable sandstone-type uranium deposit in Songliao Basin [31], the CO 2 + O 2 in situ leaching field test was performed in 2006, and then the industrial production of CO 2 + O 2 in situ leaching started in six minable layers of Qianjiadian uranium deposit from 2009 [32]. The uranium ore-bearing beds in the Qianjiadian uranium deposit are thus selected as the study object in this work.…”

Section: Geological Backgroundmentioning

confidence: 99%

Mineral Composition and Full-Scale Pore Structure of Qianjiadian Sandstone-Type Uranium Deposits: Application for In Situ Leaching Mining

et al. 2022

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In situ leaching (ISL) is becoming the main mining practice for sandstone-type uranium deposits in China. The key to ISL technology is to aid the leaching solution in contacting the ore bed over a large range, which will induce a series of chemical reactions to extract uranium; thus, it is essential to thoroughly understand the reservoir physical properties of uranium deposits. Taking the Qianjiadian sandstone-type uranium deposits (southern Songliao Basin, China) as an example, the mineral composition and pore structure of samples in different layers were measured using X-ray diffraction (XRD), thin section analysis (TSA), low-temperature N2 adsorption (LTN2A), and mercury intrusion porosimetry (MIP), and their influences on the ISL effect were analyzed. The results show that more than 65% of the minerals in the Qianjiadian uranium deposits are felsic minerals, and the carbonate minerals, clay minerals, and augite are auxiliary minerals. The primary intergranular pores, intergranular-dissolved pores, intragranular-dissolved pores, intercrystalline pores, and microfractures are developed in uranium deposits with various lithologies to different degrees. The macropores ( >1000 nm) and mesopores (100-1000 nm) of medium sandstone, argillaceous sandstone, and siltstone are well developed; in contrast, the proportions of micropores ( <10 nm) and transition pores (10-100 nm) in coarse sandstone, fine sandstone, and sandy mudstone are quite high. The heterogeneity of pores in uranium deposits of different lithologies is strong and influences the mineral composition and its fabric mode. Coarse sandstone, fine sandstone, and sandy mudstone are favorable for ISL mining in Qianjiadian uranium deposits because their permeability is above the required permeability threshold of ISL. The uranium deposits with permeability below the threshold are recommended to adopt the blasting-enhanced permeability method to improve their permeability for achieving large-scale and high-efficiency ISL mining. This study can provide guidance for the selection of favorable ore beds for ISL mining and reservoir stimulation methods in low-permeability sandstone-type uranium deposits.

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Quantifying the impact of mineralogical heterogeneity on reactive transport modeling of CO2 + O2 in-situ leaching of uranium

Cited by 11 publications

References 31 publications

Multi‐Isotope Based Identification and Quantification of Oxygen Consuming Processes in Uranium Hosting Aquifers With CO₂ + O₂ In Situ Leaching

Multi‐Isotope Based Identification and Quantification of Oxygen Consuming Processes in Uranium Hosting Aquifers With CO₂ + O₂ In Situ Leaching

Assessment of the Greenhouse Gas Footprint and Environmental Impact of CO₂ and O₂ in situ Uranium Leaching

Mineral Composition and Full-Scale Pore Structure of Qianjiadian Sandstone-Type Uranium Deposits: Application for In Situ Leaching Mining

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Quantifying the impact of mineralogical heterogeneity on reactive transport modeling of CO2 + O2 in-situ leaching of uranium

Cited by 11 publications

References 31 publications

Multi‐Isotope Based Identification and Quantification of Oxygen Consuming Processes in Uranium Hosting Aquifers With CO2 + O2 In Situ Leaching

Multi‐Isotope Based Identification and Quantification of Oxygen Consuming Processes in Uranium Hosting Aquifers With CO2 + O2 In Situ Leaching

Assessment of the Greenhouse Gas Footprint and Environmental Impact of CO2 and O2 in situ Uranium Leaching

Mineral Composition and Full-Scale Pore Structure of Qianjiadian Sandstone-Type Uranium Deposits: Application for In Situ Leaching Mining

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Product

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Multi‐Isotope Based Identification and Quantification of Oxygen Consuming Processes in Uranium Hosting Aquifers With CO₂ + O₂ In Situ Leaching

Multi‐Isotope Based Identification and Quantification of Oxygen Consuming Processes in Uranium Hosting Aquifers With CO₂ + O₂ In Situ Leaching

Assessment of the Greenhouse Gas Footprint and Environmental Impact of CO₂ and O₂ in situ Uranium Leaching