1
|
Lu C, Xiu W, Yang B, Zhang H, Lian G, Zhang T, Bi E, Guo H. Natural Attenuation of Groundwater Uranium in Post-Neutral-Mining Sites Evidenced from Multiple Isotopes and Dissolved Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:12674-12684. [PMID: 38965983 DOI: 10.1021/acs.est.4c04498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/06/2024]
Abstract
Although natural attenuation is an economic remediation strategy for uranium (U) contamination, the role of organic molecules in driving U natural attenuation in postmining aquifers is not well-understood. Groundwaters were sampled to investigate the chemical, isotopic, and dissolved organic matter (DOM) compositions and their relationships to U natural attenuation from production wells and postmining wells in a typical U deposit (the Qianjiadian U deposit) mined by neutral in situ leaching. Results showed that Fe(II) concentrations and δ34SSO4 and δ18OSO4 values increased, but U concentrations decreased significantly from production wells to postmining wells, indicating that Fe(III) reduction and sulfate reduction were the predominant processes contributing to U natural attenuation. Microbial humic-like and protein-like components mediated the reduction of Fe(III) and sulfate, respectively. Organic molecules with H/C > 1.5 were conducive to microbe-mediated reduction of Fe(III) and sulfate and facilitated the natural attenuation of dissolved U. The average U attenuation rate was -1.07 mg/L/yr, with which the U-contaminated groundwater would be naturally attenuated in approximately 11.2 years. The study highlights the specific organic molecules regulating the natural attenuation of groundwater U via the reduction of Fe(III) and sulfate.
Collapse
Affiliation(s)
- Chongsheng Lu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences Beijing, Beijing 100083, China
- MOE Key Laboratory of Groundwater Circulation and Environment Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China
| | - Wei Xiu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences Beijing, Beijing 100083, China
- MOE Key Laboratory of Groundwater Circulation and Environment Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China
- Institute of Earth Sciences, China University of Geosciences (Beijing), Beijing 100083, China
| | - Bing Yang
- The Fourth Research and Design Engineering Corporation of CNNC, Shijiazhuang 050021, China
| | - Haoyan Zhang
- The Fourth Research and Design Engineering Corporation of CNNC, Shijiazhuang 050021, China
| | - Guoxi Lian
- The Fourth Research and Design Engineering Corporation of CNNC, Shijiazhuang 050021, China
| | - Tianjing Zhang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences Beijing, Beijing 100083, China
- Institute of Earth Sciences, China University of Geosciences (Beijing), Beijing 100083, China
| | - Erping Bi
- MOE Key Laboratory of Groundwater Circulation and Environment Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China
| | - Huaming Guo
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences Beijing, Beijing 100083, China
- MOE Key Laboratory of Groundwater Circulation and Environment Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China
| |
Collapse
|
2
|
Seigneur N, Grozeva N, Purevsan B, Descostes M. Reactive transport modelling as a toolbox to compare remediation strategies for aquifers impacted by uranium in situ recovery. JOURNAL OF CONTAMINANT HYDROLOGY 2024; 265:104392. [PMID: 38954926 DOI: 10.1016/j.jconhyd.2024.104392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 06/19/2024] [Accepted: 06/22/2024] [Indexed: 07/04/2024]
Abstract
More than 60% of worldwide uranium production is based on the In Situ Recovery mining technique. This exploitation method directly falls within the scope of the applications of reactive transport modelling to optimize uranium production and limit its associated environmental impact. We propose a modelling approach which is able to represent the natural evolution of an aquifer impacted by an ISR test performed using sulfuric acid. The model is calibrated on a 12 year-long data series obtained from 12 monitoring wells surrounding an ISR pilot cell. Through this process-based approach, we simulate the impact of several remediation strategies that can be considered in these contexts. In particular, we model the impact of Pump & Treat combined with reverse osmosis, as well as the circulation of non-impacted fluids through the reservoir with different operating strategies. Our approach allows to compare the effectiveness of these strategies. For this small-scale ISR pilot, monitored natural attenuation constitutes an interesting approach due to its faster pH recovery time with respect to Pump & Treat (5-10 years to pH ∼ 6), whose efficiency can be improved by the addition of exchangeable cations. Circulation of unimpacted fluids can reduce pH recovery times if performed for periods longer than the ISR exploitation and/or deployed with a delay. Combined with an economic evaluation of their deployment, this modelling approach can help the mining operator select and design optimal remediation strategies from an environmental and economical standpoint.
Collapse
Affiliation(s)
- Nicolas Seigneur
- Mines Paris PSL, PSL University, Centre de Géosciences, 35 Rue St Honoré, Fontainebleau, 77300, France.
| | - Niya Grozeva
- Mines Paris PSL, PSL University, Centre de Géosciences, 35 Rue St Honoré, Fontainebleau, 77300, France; ORANO Mining, 125 Avenue de Paris, Châtillon, Paris 92320, France
| | - Bayarmaa Purevsan
- Badrakh Energy, ICC Tower, Jamiyan Gun street, 9, District Sukhbaatar, Ulaanbaatar 14210, Mongolia
| | - Michaël Descostes
- Mines Paris PSL, PSL University, Centre de Géosciences, 35 Rue St Honoré, Fontainebleau, 77300, France; ORANO Mining, 125 Avenue de Paris, Châtillon, Paris 92320, France
| |
Collapse
|
3
|
Bonnet M, Robin V, Parrotin F, Grozeva N, Seigneur N, Batbaatar ME, Descostes M. Influence of clay minerals on pH and major cation concentrations in acid-leached sands: Column experiments and reactive-transport modeling. JOURNAL OF CONTAMINANT HYDROLOGY 2024; 264:104363. [PMID: 38805790 DOI: 10.1016/j.jconhyd.2024.104363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 03/28/2024] [Accepted: 05/06/2024] [Indexed: 05/30/2024]
Abstract
A series of laboratory experiments are conducted to simulate the acidification and subsequent recovery of a sand aquifer exploited by in situ recovery (ISR) mining. A sulfuric acid solution (pH 2) is first injected into a column packed with sand from the Zoovch Ovoo uranium roll front deposit (Mongolia). Solutions representative of local groundwater or enriched in cations (Na+, Mg2+) are then circulated through the column to simulate the inflow of aquifer water. pH and major ion concentrations (Na+, Cl-, SO42-, Ca2+, Mg2+, K+) measured at the column outlet reproduce the overall evolution of porewater chemistry observed in the field. The presence of minor quantities of swelling clay minerals (≈6 wt% smectite) is shown to exert an important influence on the behavior of inorganic cations, particularly H+, via ion-exchange reactions. Numerical models that consider ion-exchange on smectite as the sole solid-solution interaction are able to reproduce variations in pH and cation concentrations in the column experiments. This highlights the importance of clay minerals in controlling H+ mobility and demonstrates that sand from the studied aquifer can be described to a first order as an ion-exchanger. The present study confirms the key role of clay minerals in controlling water chemistry in acidic environments through ion-exchange processes. In a context of managing the long-term environmental footprint of industrial and mining activities (ISR, acid mine drainage…), this work will bring insights for modeling choices and identification of key parameters to help operators to define their production and/or remediation strategies.
Collapse
Affiliation(s)
- Marine Bonnet
- E2Lim, University of Limoges, 123 Avenue Albert Thomas, CEDEX, 87060 Limoges, France.
| | - Valentin Robin
- E2Lim, University of Limoges, 123 Avenue Albert Thomas, CEDEX, 87060 Limoges, France.
| | - Flora Parrotin
- E2Lim, University of Limoges, 123 Avenue Albert Thomas, CEDEX, 87060 Limoges, France; IC2MP, HydrASA, UMR 7285 CNRS/University of Poitiers, 86073 Poitiers, France; ORANO Mining, Environmental R&D Department, 125 Avenue de Paris, 92330 Châtillon, France.
| | - Niya Grozeva
- Mines Paris, PSL University, Center for geosciences and geoengineering, 35 rue St Honoré, 77330 Fontainebleau, France.
| | - Nicolas Seigneur
- Mines Paris, PSL University, Center for geosciences and geoengineering, 35 rue St Honoré, 77330 Fontainebleau, France.
| | - Munkh-Erdene Batbaatar
- Badrakh Energy LLC, Jamyan Gun Avenue - 9, Sukhbaatar district, 1st khoroo, UB-14240, Mongolia.
| | - Michael Descostes
- Mines Paris, PSL University, Center for geosciences and geoengineering, 35 rue St Honoré, 77330 Fontainebleau, France; ORANO Mining, Environmental R&D Department, 125 Avenue de Paris, 92330 Châtillon, France.
| |
Collapse
|
4
|
Lévy L, Bording TS, Fiandaca G, Christiansen AV, Madsen LM, Bennedsen LF, Jørgensen TH, MacKinnon L, Christensen JF. Managing the remediation strategy of contaminated megasites using field-scale calibration of geo-electrical imaging with chemical monitoring. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 920:171013. [PMID: 38369154 DOI: 10.1016/j.scitotenv.2024.171013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 01/29/2024] [Accepted: 02/14/2024] [Indexed: 02/20/2024]
Abstract
Groundwater contamination is a threat to drinking water resources and ecosystems. Remediation by injection of chemical reagents into the aquifer may be preferred to excavation to reduce cost and environmental footprint. Yet, successful remediation requires complete contact between contamination and reagents. Subsurface heterogeneities are often responsible for diffusion into low-permeable zones, which may inhibit this contact. Monitoring the spatial distribution of injected reagents over time is crucial to achieve complete interaction. Source zone contamination at megasites is particularly challenging to remediate and monitor due to the massive scale and mixture of contaminants. Source zone remediation at Kærgård Plantation megasite (Denmark) is monitored here, with a new methodology, using high-resolution cross-borehole electrical resistivity tomography (XB-ERT) imaging calibrated by chemical analyses on groundwater samples. At this site, high levels of toxic non-aqueous phase liquids (NAPL) are targeted by in-situ chemical oxidation using activated persulfate. It may take numerous injection points with extensive injection campaigns to distribute reagents, which requires an understanding of how reagent may transport within the aquifer. A geophysical (XB-ERT) monitoring network of unprecedented size was installed to identify untreated zones and help manage the remediation strategy. The combination of spatially continuous geophysical information with discrete but precise chemical information, allowed detailed monitoring of sulfate distribution, produced during persulfate activation. Untreated zones identified in the first remediation campaign were resolved in the second campaign. The monitoring allowed adjusting the number of injection screens and the injection strategy from one campaign to the next, which resulted in better persulfate distribution and contaminant degradation in the second campaign. Furthermore, geophysical transects repeated over the timespan of a remediation campaign allowed high-resolution time-lapse imaging of reagent transport, which could in the future improve the predictability of transport models, compared to only using on a-priori assumptions of the hydraulic conductivity field.
Collapse
|
5
|
Guillon S, Girard JF, Williard E, Virlogeux D, Descostes M. Modeling subsurface contaminant transport from a former open-pit uranium mine in fractured granites (La Ribière, France): Reducing uncertainties with geophysics. JOURNAL OF CONTAMINANT HYDROLOGY 2024; 263:104343. [PMID: 38631090 DOI: 10.1016/j.jconhyd.2024.104343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 04/08/2024] [Accepted: 04/12/2024] [Indexed: 04/19/2024]
Abstract
The long-term management of tailings from former uranium (U) mines requires an in-depth understanding of the hydrogeological processes and water flow paths. In France, most of the legacy U mines are located in fractured crystalline (plutonic) rocks, where the intrinsic subsurface heterogeneity adds to the uncertainties about the former extraction and milling activities and the state of the mine when production was ceased. U ores were mainly processed by sulfuric acid leaching, leading to high-sulfate-content mill tailings now contained in several tailing storage facilities (TSFs). The La Ribière site, located in western central France, is a former open-pit and underground U mine, closed in 1992 and used to store mill tailings. This site is being used as a test case to establish a workflow in order to explain and predict water flow and subsurface contaminant transport. A conceptual model of water flow and sulfate transport, at the scale of the La Ribière watershed, is first developed based on available information and hydrogeochemical monitoring. Recent geophysical investigations allows refining this model. Electrical Resistivity Tomography (ERT) proves to be efficient at localizing the extent of the highly conductive sulfate plume inherited from the U-mill tailings, but also at imaging the weathering profile. Magnetic Resonance Sounding (MRS), despite the limited signal intensity due to the low porosity in crystalline rocks, gives some insight into the porosity values, the depth of the fractured layer and the location of the low-porosity ore-processing muds. Based on this conceptual model, a 3D flow and non-reactive transport model with the METIS code is developed and calibrated. This model allows predicting the evolution of the sulfate plume, but will also be used in future investigations, to build reactive transport models with simplified hydrogeology for U and other reactive contaminants.
Collapse
Affiliation(s)
- S Guillon
- Mines Paris, PSL University, Centre de Geosciences, 35 rue Saint Honoré, 77300 Fontainebleau, France.
| | - J-F Girard
- ITES, Institut Terre et Environnement de Strasbourg, University of Strasbourg, CNRS, France
| | | | - D Virlogeux
- ORANO Mining, Chatillon, France; GEOYODA Consultant, Bordeaux, France
| | - M Descostes
- Mines Paris, PSL University, Centre de Geosciences, 35 rue Saint Honoré, 77300 Fontainebleau, France; ORANO Mining, Chatillon, France
| |
Collapse
|
6
|
Parrotin F, Dazas B, Billon S, Chedozeau R, Savoye S, Descostes M, Tertre E. Role of zeolite content on the sorption properties of analcime-rich rocks from the Abinky Formation (Niger). THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 925:171615. [PMID: 38462009 DOI: 10.1016/j.scitotenv.2024.171615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 03/06/2024] [Accepted: 03/08/2024] [Indexed: 03/12/2024]
Abstract
The Abinky formation, composed of analcimolites (i.e., rocks with <70 wt% analcime), underlies Tchirezrine II, which hosts the Imouraren (Niger) uranium deposit. A potential mining project is under consideration to recover U by in situ acid leaching. Analcimolites are uncommon rocks, and assessing their ion-exchange properties is the first step to understand and predict the mobility of aqueous species in these formations. The objective of this study is then to understand the link between the Cation Exchange Capacities (CEC) of analcimolites as a function of their analcime content and associated crystal chemistry. Mineral quantification was performed by Rietveld refinement constrained by local chemical analysis with scanning electron microscopy coupled with Energy Dispersive Spectrometry. CEC were obtained at neutral pH by performing NH4+-for-Na+ exchange (CECNa/NH4), and Na+/H+ ion exchange experiments were performed with 4 analcimolites. Results showed that the analcime crystal chemistry deduced from Rietveld refinement was in good agreement with that obtained from SEM analysis (1.99 < Si/Al < 2.53). The results showed that all samples had a positive correlation between CECNa/NH4 and analcime content until ~30 meq/100 g for a sample containing ~85wt%Riet. of analcime, and that ~6 % of the total amounts of Na+ present in the analcime could be exchanged by NH4+ and H+. Based on Si and Al aqueous measurements, results showed that exchange with Na+ is the main process consuming H+ during Na+/H+ exchange when pH > 3.5. These experimental data were then interpreted by considering a single site equal to the CECNa/NH4 value, specific for each analcimolite, and a selectivity coefficient equal to log KNa/H = 1.3 (Gaines Thomas convention) being equal for all samples investigated. Finally, these data were used to assess the role played by Na+/H+ exchange in the pH evolution of the pore water of an analcime-rich rock subjected to dynamic acidification.
Collapse
Affiliation(s)
- Flora Parrotin
- IC2MP, Equipe HydrASA, UMR 7285/Université de Poitiers, 86073 Poitiers, France; ORANO Mining, Environmental R&D Dpt., 92320 Chatillon, France.
| | - Baptiste Dazas
- IC2MP, Equipe HydrASA, UMR 7285/Université de Poitiers, 86073 Poitiers, France
| | - Sophie Billon
- IC2MP, Equipe HydrASA, UMR 7285/Université de Poitiers, 86073 Poitiers, France
| | - Raphaël Chedozeau
- IC2MP, Equipe HydrASA, UMR 7285/Université de Poitiers, 86073 Poitiers, France
| | - Sébastien Savoye
- Université Paris-Saclay, CEA, Service de Physico-Chimie, 91191 Gif-sur-Yvette, France
| | - Michaël Descostes
- ORANO Mining, Environmental R&D Dpt., 92320 Chatillon, France; Centre de Géosciences, MINES Paris, PSL University, 35 rue St Honoré, 77300 Fontainebleau, France
| | - Emmanuel Tertre
- IC2MP, Equipe HydrASA, UMR 7285/Université de Poitiers, 86073 Poitiers, France
| |
Collapse
|
7
|
Lefeuvre H, Billon S, Descostes M, Donnard J, Duval S, Sardini P. Using spectroscopic autoradiography of alpha particles for the quantitative mapping of 226Ra ultra-traces in geo-materials. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2024; 273:107392. [PMID: 38342022 DOI: 10.1016/j.jenvrad.2024.107392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/19/2024] [Accepted: 01/24/2024] [Indexed: 02/13/2024]
Abstract
The measurement of 226Ra and the identification of 226Ra-bearing minerals are important for studying the behavior of radium in the environment. Various instruments for measuring 226Ra are currently used: among the radiometric techniques that measure in bulk (no spatialization), there are gamma spectrometers and alpha spectrometers. Other instruments such as SEM-EDS can map the chemical elements thus providing information on the distribution of 226Ra, but are limited for ultra-trace analyses on natural geomaterials. Finally, autoradiography techniques can locate radioactivity, but are limited to the identification of the contribution of 226Ra when the 238U series is complete. This study focuses on spectroscopic autoradiography, a method for measuring both the energy of the alpha particle emissions and their positions on the autoradiograph. A gas detector based on a parallel ionization multiplier technology was used for this purpose. Alpha particle energy is dependent on the emitting radionuclides. In order to track the 226Ra, the energy spectrum of the 238U series was studied with modeling software. It appears possible to apply a thresholding on the energy spectrum to discriminate the 226Ra from the first alpha emitters of the 238U decay chain (i.e. 238U, 234U and 230Th, all below 5 MeV). The developed method was applied to a U-mill tailing sample prepared as a thin section. The sample was heterogeneous in terms of radioactivity and was not at secular equilibrium with 238U, as expected. The 226Ra was identified and localized, and different regions of interest were also analyzed with SEM-EDS elements cartography. This revealed 226Ra-rich barite (BaSO₄) phases measured at 3 ppmRa on average and containing no uranium; and uranium in siderite (FeCO3), showing a strong 226Ra deficit compared with secular equilibrium. Spectroscopic autoradiography opens up possibilities for the analysis of heterogeneous geological samples containing natural alpha emitters such as 238U and 226Ra: the 226Ra can be localized and quantified at ultra-trace content, and the method developed can also identify newly (young) uranium phases by measuring 238U/226Ra activity disequilibrium.
Collapse
Affiliation(s)
- Hugo Lefeuvre
- ERM (SARL), 7 rue Albert Turpain, 86000, Poitiers, France; IC2MP - HydrASA, Poitiers University UMR, 7285, CNRS, France
| | - Sophie Billon
- IC2MP - HydrASA, Poitiers University UMR, 7285, CNRS, France
| | - Michael Descostes
- ORANO Environmental R&D Dpt, 125 Av. de Paris, 92320, Châtillon, Paris, France; Centre de Géosciences, MINES ParisTech, PSL University, 35 rue St Honoré, 77300, Fontainebleau, France
| | | | - Samuel Duval
- AI4R (SAS), 2 rue Alfred Kastler, Nantes, France
| | - Paul Sardini
- IC2MP - HydrASA, Poitiers University UMR, 7285, CNRS, France.
| |
Collapse
|
8
|
Escario S, Seigneur N, Collet A, Regnault O, de Boissezon H, Lagneau V, Descostes M. A reactive transport model designed to predict the environmental footprint of an 'in-situ recovery' uranium exploitation. JOURNAL OF CONTAMINANT HYDROLOGY 2023; 254:104106. [PMID: 36634485 DOI: 10.1016/j.jconhyd.2022.104106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 10/25/2022] [Accepted: 11/02/2022] [Indexed: 06/17/2023]
Abstract
Worldwide, most uranium production relies on the 'in situ recovery' (ISR) extraction technique. This consists of dissolving the ore using a leaching solution (acid or alkaline) directly within the deposit through a series of injection and extraction wells. Due to the nature of the injected ISR solutions, the water quality of the aquifer could be affected. Reactive transport modeling is a powerful tool for predicting fluid flow and geochemical reactions in ISR reservoirs. In this study we present a coupled 3D environmental geochemical model (EGM) (based on the HYTEC reactive transport software), capable of predicting the physico-chemical conditions in an acid-leaching ISR uranium mine and its environmental footprint on the aquifer in the years following the closure of the production block. The model was validated at the KATCO mine (Kazakhstan) on two different and independent production blocks, over 10 years after their closure. The model shows that incorporating two main geochemical processes, (1) cationic sorption on clay surfaces (smectite-beidellite) and (2) precipitation of gypsum (CaSO4.2H2O), successfully reproduces the measured well data (pH, acidity and SO4) over short- and long-term time scales. Clay surface sites remain mostly saturated in protons during the production phase. Simulations show that sorbed protons on the clay surfaces maintains the acid conditions for a longer period of time. The environmental impact model was also compared to a pre-existing model specifically developed for production simulation purposes: differences are observed as expected for the uranium production, but also for the impact distances, due to differences in the considered reactive mineralogical paragenesis. Thus, the choice of geochemical model should be made with due regard for the desired objectives. This work will assist the mine operator by providing a tool capable of assessing both the short- and long-term environmental footprints of the ISR production operation conditions and of identifying the best remediation strategy.
Collapse
Affiliation(s)
- S Escario
- PSL University/Mines ParisTech, Centre de Géosciences, 35 rue Saint-Honoré, 77305 Fontainebleau, France; ORANO Mining, 125 avenue de Paris, 92320 Châtillon, France.
| | - N Seigneur
- PSL University/Mines ParisTech, Centre de Géosciences, 35 rue Saint-Honoré, 77305 Fontainebleau, France
| | - A Collet
- PSL University/Mines ParisTech, Centre de Géosciences, 35 rue Saint-Honoré, 77305 Fontainebleau, France; ORANO Mining, 125 avenue de Paris, 92320 Châtillon, France
| | - O Regnault
- PSL University/Mines ParisTech, Centre de Géosciences, 35 rue Saint-Honoré, 77305 Fontainebleau, France; ORANO Mining, 125 avenue de Paris, 92320 Châtillon, France
| | - H de Boissezon
- ORANO Mining, 125 avenue de Paris, 92320 Châtillon, France
| | - V Lagneau
- PSL University/Mines ParisTech, Centre de Géosciences, 35 rue Saint-Honoré, 77305 Fontainebleau, France
| | - M Descostes
- PSL University/Mines ParisTech, Centre de Géosciences, 35 rue Saint-Honoré, 77305 Fontainebleau, France; ORANO Mining, 125 avenue de Paris, 92320 Châtillon, France
| |
Collapse
|
9
|
Parrotin F, Robin V, Beaucaire C, Descostes M, Tertre E. Competitive ion-exchange reactions of Pb(II) (Pb 2+/PbCl +) and Ra(II) (Ra 2+) on smectites: Experiments, modeling, and implication for 226Ra(II)/ 210Pb(II) disequilibrium in the environment. CHEMOSPHERE 2023; 313:137369. [PMID: 36427575 DOI: 10.1016/j.chemosphere.2022.137369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 06/16/2023]
Abstract
In this study, new experimental data for the adsorption of lead onto a swelling clay mineral with a tetrahedral charge (beidellite) at the ultratrace level (<10-10 M) are presented. The data were interpreted using an ion-exchange multisite model that considers the sorption of major cations (including H+), which always compete with trace elements for sorption onto mineral surfaces in natural environments. The ability of the proposed model to predict experimental Kd values under various conditions of ionic strength (fixed by NaCl solutions) and aqueous cation compositions (including Pb2+ and PbCl+) was tested. The proposed model was applied to experimental data previously published for other types of swelling clay minerals, and the results were compared with the results obtained using previously published models. The preferential adsorption of chloride ion pairs, as well as the effect of the swelling clay crystal chemistry on lead adsorption, were assessed. Finally, the selective adsorption behavior of 226Ra compared to 210Pb was demonstrated, which has implications for the study of many environmental processes using isotope partitioning.
Collapse
Affiliation(s)
- Flora Parrotin
- IC2MP, Equipe HydrASA, UMR 7285 CNRS/Université de Poitiers, 86073, Poitiers, France; E2Lim, UR 24 133, Université de Limoges, 123 avenue Albert Thomas, 87060 Limoges Cedex, France; Orano Mining, Environmental R&D Dpt., 125 avenue de Paris, 92320, Chatillon, France.
| | - Valentin Robin
- E2Lim, UR 24 133, Université de Limoges, 123 avenue Albert Thomas, 87060 Limoges Cedex, France
| | - Catherine Beaucaire
- CEA, Centre d'Etudes de Saclay, DANS/DPC/SECR/L3MR, 91191, Gif sur Yvette, France
| | - Michael Descostes
- Orano Mining, Environmental R&D Dpt., 125 avenue de Paris, 92320, Chatillon, France; Centre de Géosciences, MINES ParisTech, PSL University, 35 rue St Honoré, 77300, Fontainebleau, France
| | - Emmanuel Tertre
- IC2MP, Equipe HydrASA, UMR 7285 CNRS/Université de Poitiers, 86073, Poitiers, France
| |
Collapse
|
10
|
Besançon C, Sardini P, Savoye S, Descostes M, Gérard M. Quantifying 226Ra activity in a complex assemblage of 226Ra-bearing minerals using alpha autoradiography and SEM/EDS. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 251-252:106951. [PMID: 35780670 DOI: 10.1016/j.jenvrad.2022.106951] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 05/12/2022] [Accepted: 06/17/2022] [Indexed: 06/15/2023]
Abstract
226Ra is an ultra-trace element with important environmental implications for many industries (including water treatment and oil and mineral extraction). Its extremely low concentrations in natural environments do not allow for direct observation and measurement of the 226Ra-bearing minerals governing 226Ra mobility. To better understand the retention processes for 226Ra in rocks and soil, a synthesized assemblage of 226Ra-doped minerals was made, combining montmorillonite, ferrihydrite and barite. A new methodology was developed using alpha activity maps acquired using alpha autoradiography, and elemental maps by using SEM/EDS. These maps were processed using a global approach, considering the entirety of the signal. The comparison of the alpha activity map and the elemental map enabled a correlation to be established between the 226Ra activity and the chemical composition and identification of the main 226Ra-bearing mineral of the assemblage, from which we were able to estimate the contribution of each mineral to the total activity of the assemblage, and to quantify the 226Ra-activity for each mineral. This methodology makes it possible to link mineralogy and occurrence of 226Ra at the scale of the mineral (tens of μm). It can be applied to natural samples, including fine-grained samples with a complex mineralogy.
Collapse
Affiliation(s)
- Clémence Besançon
- Environmental R&D Department, ORANO Mining, 125 Avenue de Paris, 92320, Chatillon, France; Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, 4 Place Jussieu, 75005, Paris, France.
| | - Paul Sardini
- Institut de Chimie des Milieux et des Matériaux de Poitiers (IC2MP), Université de Poitiers, Rue Michel Brunet, Bat. 35, 86000, Poitiers, France
| | - Sébastien Savoye
- Des, Service d'Etude du Comportement des Radionucléides (SECR), CEA, Université Paris-Saclay, 91191, Gif-sur-Yvette, France
| | - Michael Descostes
- Environmental R&D Department, ORANO Mining, 125 Avenue de Paris, 92320, Chatillon, France; Centre de Géosciences, MINES ParisTech, PSL University, 35 Rue St Honoré, Fontainebleau, 77300, France
| | - Martine Gérard
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, 4 Place Jussieu, 75005, Paris, France
| |
Collapse
|
11
|
Coral T, Placko AL, Beaufort D, Tertre E, Bernier-Latmani R, Descostes M, De Boissezon H, Guillon S, Rossi P. Biostimulation as a sustainable solution for acid neutralization and uranium immobilization post acidic in-situ recovery. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 822:153597. [PMID: 35114226 DOI: 10.1016/j.scitotenv.2022.153597] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/24/2022] [Accepted: 01/28/2022] [Indexed: 06/14/2023]
Abstract
Major uranium (U) deposits worldwide are exploited by acid leaching, known as 'in-situ recovery' (ISR). ISR involves the injection of an acid fluid into ore-bearing aquifers and the pumping of the resulting metal-containing solution through cation exchange columns for the recovery of dissolved U. Rehabilitation of ISR-impacted aquifers could be achieved through natural attenuation, or via biostimulation of autochthonous heterotrophic microorganisms due to the associated acid neutralization and trace metal immobilization. In this study, we analyzed the capacity of pristine aquifer sediments impacted by diluted ISR fluids to buffer pH and immobilize U. The experimental setup consisted of glass columns, filled with sediment from a U ore-bearing aquifer, through which diluted ISR fluids were flowed continuously. The ISR solution was obtained from ISR mining operations at the Muyunkum and Tortkuduk deposits in Kazakhstan. Following this initial phase, columns were biostimulated with a mix of molasses, yeast extract and glycerol to stimulate the growth of autochthonous heterotrophic communities. Experimental results showed that this amendment efficiently promoted the activity of acid-tolerant bacterial guilds, with pH values rising from 4.8 to 6.5-7.0 at the outlet of the stimulated columns. The reduction of sulfate, nitrate, and metals as well as dissimilatory nitrate reduction to ammonia induced the rise in pH values, in agreement with geochemical modelling results. Biostimulation efficiently promoted the complete immobilization of U, with the accumulation of up to 3343 ppm in the first few centimeters of the columns. Synchrotron analysis and SEM-EDS revealed that up to 60% of the injected hexavalent U was immobilized as tetravalent non-crystalline U onto bacterial cell surfaces. 16S rDNA amplicon analysis and qPCR data suggested a predominant role played for members of the Phylum Firmicutes (from the genera Clostridium, Pelosinus and Desulfosporosinus) in biological U reduction and immobilization.
Collapse
Affiliation(s)
- Thomas Coral
- Central Environmental Laboratory, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, Station 2, 1015 Lausanne, Switzerland
| | - Anne-Laure Placko
- Orano Mining, Environmental R&D Dpt., 125 avenue de Paris, 92320 Chatillon, France
| | - Daniel Beaufort
- Université de Poitiers/CNRS, UMR 7285 IC2MP, Equipe HydrASA, 5 rue Albert Turpain, 86073 Poitiers Cedex 9, France.
| | - Emmanuel Tertre
- Université de Poitiers/CNRS, UMR 7285 IC2MP, Equipe HydrASA, 5 rue Albert Turpain, 86073 Poitiers Cedex 9, France.
| | - Rizlan Bernier-Latmani
- Environmental Microbiology Laboratory, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, Station 6, 1015 Lausanne, Switzerland.
| | - Michael Descostes
- Orano Mining, Environmental R&D Dpt., 125 avenue de Paris, 92320 Chatillon, France; Centre de Géosciences, MINES ParisTech, PSL University. 35 rue St Honoré, 77300 Fontainebleau, France
| | - Hélène De Boissezon
- Orano Mining, Environmental R&D Dpt., 125 avenue de Paris, 92320 Chatillon, France
| | - Sophie Guillon
- Centre de Géosciences, MINES ParisTech, PSL University. 35 rue St Honoré, 77300 Fontainebleau, France.
| | - Pierre Rossi
- Central Environmental Laboratory, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, Station 2, 1015 Lausanne, Switzerland.
| |
Collapse
|
12
|
Modeling Uranium Transport in Rough-Walled Fractures with Stress-Dependent Non-Darcy Fluid Flow. MATHEMATICS 2022. [DOI: 10.3390/math10050702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The reactive-transportation of radioactive elements in fractured rock mass is critical to the storage of radioactive elements. To describe the reactive-transportation and distribution morphology of a uranium-containing solution, a stress-dependent reactive transport model was developed, and the simulator of FLAC3D-CFD was employed. The uranium transport experiment subjected to the variation of confining stress of 5–19 MPa and hydraulic pressure of 0.5–3.5 MPa was conducted in fractured rock mass. The results show that the uranium-containing solution transport and distribution is significantly dependent on the evolution of the connected channel in rough-walled fracture, which is significantly influenced by the confining stress and hydraulic pressure. In more detail, the increase of confining stress resulted in the anisotropic of seepage channel in aperture, and corresponding turbulence flow and uranium retention were presented at the fracture aperture of 2–5 μm. As the increase of hydraulic pressure, flow regime evolved from the inertial flow to vortex flow, and the transformation region is 16 MPa confining stress and 1.5 MPa hydraulic pressure. The evolution of loading paths also dominates the flow and solute transport, and high seepage speed and strong solute transport were presented at the k = 1 (ratio of vertical stress loading to horizontal stress unloading), and a laminar flow and weak solute transport were presented at k = 0.
Collapse
|
13
|
Long-Term Evolution of Uranium Mobility within Sulfated Mill Tailings in Arid Regions: A Reactive Transport Study. MINERALS 2021. [DOI: 10.3390/min11111201] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Management of mill tailings is an important part of mining operations that aims at preventing environmental dispersion of contaminants of concern. To this end, geochemical models and reactive transport modeling provide a quantitative assessment of the mobility of the main contaminants. In arid regions with limited rainfall and intense evaporation, solutes transport may significantly differ from the usual gravity-driven vertical flow. In the uranium tailings of the Cominak mine (Niger), these evaporative processes resulted in the crystallization of gypsum, and to a lesser extent jarosite, and in the formation of surface levels of sulfated gypcrete, locally enriched in uranium. We present a fully coupled reactive transport modeling approach using HYTEC, encompassing evaporation, to quantitatively reproduce the complex sequence of observed coupled hydrogeochemical processes. The sulfated gypcrete formation, porosity evolution and solid uranium content were successfully reproduced at the surface and paleosurfaces of the tailing deposit. Simulations confirm that high solubility uranyl-sulfate phase may form at the atmospheric boundary where evaporation takes place, which would then be transformed into uranyl-phosphate phases after being watered or buried under fresh tailings. As these phases usually exhibit a lower solubility, this transition is beneficial for mine operators and tailings management.
Collapse
|