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Arteaga A, Arino T, Moore GC, Bustos JL, Horton MK, Persson KA, Li J, Stickle WF, Kohlgruber TA, Surbella RG, Nyman M. The Role of Alkalis in Orchestrating Uranyl-Peroxide Reactivity Leading to Direct Air Capture of Carbon Dioxide. Chemistry 2024; 30:e202301687. [PMID: 38466912 DOI: 10.1002/chem.202301687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 03/10/2024] [Accepted: 03/11/2024] [Indexed: 03/13/2024]
Abstract
Spectator ions have known and emerging roles in aqueous metal-cation chemistry, respectively directing solubility, speciation, and reactivity. Here, we isolate and structurally characterize the last two metastable members of the alkali uranyl triperoxide series, the Rb+ and Cs+ salts (Cs-U1 and Rb-U1). We document their rapid solution polymerization via small-angle X-ray scattering, which is compared to the more stable Li+, Na+ and K+ analogues. To understand the role of the alkalis, we also quantify alkali-hydroxide promoted peroxide deprotonation and decomposition, which generally exhibits increasing reactivity with increasing alkali size. Cs-U1, the most unstable of the uranyl triperoxide monomers, undergoes ambient direct air capture of CO2 in the solid-state, converting to Cs4[UVIO2(CO3)3], evidenced by single-crystal X-ray diffraction, transmission electron microscopy, and Raman spectroscopy. We have attempted to benchmark the evolution of Cs-U1 to uranyl tricarbonate, which involves a transient, unstable hygroscopic solid that contains predominantly pentavalent uranium, quantified by X-ray photoelectron spectroscopy. Powder X-ray diffraction suggests this intermediate state contains a hydrous derivative of CsUVO3, where the parent phase has been computationally predicted, but not yet synthesized.
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Affiliation(s)
- Ana Arteaga
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331, USA
- Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA 99354, USA
| | - Trevor Arino
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331, USA
- current address, Department of Nuclear Chemistry U.C. Berkeley, Berkeley, California, 94720, USA
| | - Guy C Moore
- Department of Materials Science and Engineering, U. C. Berkeley, California, 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jenna L Bustos
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331, USA
| | - Matthew K Horton
- Department of Materials Science and Engineering, U. C. Berkeley, California, 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Kristin A Persson
- Department of Materials Science and Engineering, U. C. Berkeley, California, 94720, USA
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jun Li
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331, USA
| | | | | | - Robert G Surbella
- Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA 99354, USA
| | - May Nyman
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331, USA
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2
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van Veelen A, Hickam SM, Edwards NP, Webb SM, Clark DL, Wilkerson MP, Pugmire AL, Bargar JR. Trace Impurities Identified as Forensic Signatures in CMX-5 Fuel Pellets Using X-ray Spectroscopic Techniques. Anal Chem 2022; 94:7084-7091. [PMID: 35512178 DOI: 10.1021/acs.analchem.2c00629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Small-particle analysis is a highly promising emerging forensic tool for analysis of interdicted special nuclear materials. Integration of microstructural, morphological, compositional, and molecular impurity signatures could provide significant advancements in forensic capabilities. We have applied rapid, high-sensitivity, hard X-ray synchrotron chemical imaging to analyze impurity signatures in two differently fabricated fuel pellets from the 5th Collaborative Materials Exercise (CMX5) of the IAEA Nuclear Forensics International Working Group. The spatial distributions, chemical compositions, and morphological and molecular characteristics of impurities were evaluated using X-ray absorption near-edge structure (XANES) and X-ray fluorescence chemical imaging to discover principal impurities, their granularity, particle sizes, modes of occurrence (distinct grains vs incorporation in the UO2 lattice), and sources and mechanisms of incorporation. Differences in UO2+x stoichiometry were detected at the microscale in nominally identical UO2 ceramics (CMX5-A and CMX5-B), implying the presence of multiple UO2 host phases with characteristic microstructures and feedstock compositions. Al, Fe, Ni, W, and Zr impurities and integrated impurity signature analysis identified distinctly different pellet synthesis and processing methods. For example, two different Al, W, and Zr populations in the CMX5-B sample indicated a more complex processing history than the CMX5-A sample. K-edge XANES measurements reveal both metallic and oxide forms of Fe and Ni but with different proportions between each sample. Altogether, these observations suggest multiple sources of impurities, including fabrication (e.g., force-sieving) and feedstock (mineral oxides). This study demonstrates the potential of synchrotron techniques to integrate different signatures across length scales (angstrom to micrometer) to detect and differentiate between contrasting UO2 fuel fabrication techniques.
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Affiliation(s)
- Arjen van Veelen
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Sarah M Hickam
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Nicholas P Edwards
- SLAC National Accelerator Laboratory, Stanford Synchrotron Radiation Lightsource, Menlo Park, California 94025, United States
| | - Samuel M Webb
- SLAC National Accelerator Laboratory, Stanford Synchrotron Radiation Lightsource, Menlo Park, California 94025, United States
| | - David L Clark
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | | | - Alison L Pugmire
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - John R Bargar
- SLAC National Accelerator Laboratory, Stanford Synchrotron Radiation Lightsource, Menlo Park, California 94025, United States
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3
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Cot-Auriol M, Virot M, Micheau C, Dumas T, Le Goff X, Den Auwer C, Diat O, Moisy P, Nikitenko SI. Ultrasonically assisted conversion of uranium trioxide into uranium(vi) intrinsic colloids. Dalton Trans 2021; 50:11498-11511. [PMID: 34346448 DOI: 10.1039/d1dt01609a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Under oxidizing conditions, the corrosion of spent nuclear fuel may lead to the leaching of radionuclides including soluble uranyl-based species. The speciation of the generated chemical forms is complex and the related potential formation of colloidal species appears surprisingly poorly reported in the literature. Their formation could however contribute significantly to the mobility of radionuclides in the environment. A better knowledge in the speciation and reactivity of these species appears particularly relevant. This study describes the preparation and characterization of intrinsic uranium(vi) colloids from amorphous and crystalline UO3 in pure water assisted by 20 kHz ultrasound. In the presence of carbon monoxide preventing the sonochemical formation of hydrogen peroxide, ultrasonic treatment boosts the conversion of UO3 powder into (meta-)schoepite precipitates and yields very stable and notably concentrated uranium(vi) nanoparticles in the liquid phase. Using HR-TEM, SAXS and XAS techniques, we confirmed that the colloidal suspension is composed of quasi-spherical nanoparticles measuring ca. 3.8 ± 0.3 nm and exhibiting a schoepite-like crystallographic structure. The proposed method demonstrates the possible formation of environmentally relevant U(vi) colloidal nanoparticles appearing particularly interesting for the preparation of reference systems in the absence of added ions and capping agents.
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4
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Pandelus SB, Kennedy BJ, Murphy G, Brand HE, Keegan E, Pring A, Popelka-Filcoff RS. Phase Analysis of Australian Uranium Ore Concentrates Determined by Variable Temperature Synchrotron Powder X-ray Diffraction. Inorg Chem 2021; 60:11569-11578. [PMID: 34293259 DOI: 10.1021/acs.inorgchem.1c01562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The chemical speciation of uranium oxides is sensitive to the provenance of the samples and their storage conditions. Here, we use diffraction methods to characterize the phases found in three aged (>10 years) uranium ore concentrates of different origins as well as in situ analysis of the thermally induced structural transitions of these materials. The structures of the crystalline phases found in the three samples have been refined, using high-resolution synchrotron X-ray diffraction data. Rietveld analysis of the samples from the Olympic Dam and Ranger uranium mines has revealed the presence of crystalline α-UO2(OH)2, together with metaschoepite (UO2)4O(OH)6·5H2O, in the aged U3O8 samples, and it is speculated that this forms as a consequence of the corrosion of U3O8 in the presence of metaschoepite. The third sample, from the Beverley uranium mine, contains the peroxide [UO2(η2-O2)(H2O)2] (metastudtite) together with α-UO2(OH)2 and metaschoepite. A core-shell model is proposed to account for the broadening of the diffraction peaks of the U3O8 evident in the samples.
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Affiliation(s)
- Samantha B Pandelus
- College of Science and Engineering, Flinders University, Adelaide, South Australia 5001, Australia
| | - Brendan J Kennedy
- School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Gabriel Murphy
- School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia.,ANSTO, Lucas Heights, Sydney, New South Wales 2234, Australia
| | - Helen E Brand
- Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
| | | | - Allan Pring
- College of Science and Engineering, Flinders University, Adelaide, South Australia 5001, Australia.,School of Physical Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Rachel S Popelka-Filcoff
- College of Science and Engineering, Flinders University, Adelaide, South Australia 5001, Australia.,School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Parkville, Victoria 3010, Australia
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5
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Hanson A, Nizinski CA, McDonald LW. Effect of Diel Cycling Temperature, Relative Humidity, and Synthetic Route on the Surface Morphology and Hydrolysis of α-U 3O 8. ACS OMEGA 2021; 6:18426-18433. [PMID: 34308073 PMCID: PMC8296549 DOI: 10.1021/acsomega.1c02487] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/22/2021] [Indexed: 06/13/2023]
Abstract
The speciation and morphological changes of α-U3O8 following aging under diel cycling temperature and relative humidity (RH) have been examined. This work advances the knowledge of U-oxide hydration as a result of synthetic route and environmental conditions, ultimately giving novel insight into nuclear material provenance. α-U3O8 was synthesized via the washed uranyl peroxide (UO4) and ammonium uranyl carbonate (AUC) synthetic routes to produce unaged starting materials with different morphologies. α-U3O8 from UO4 is comprised of subrounded particles, while α-U3O8 from AUC contains blocky, porous particles approximately an order of magnitude larger than particles from UO4. For aging, a humidity chamber was programmed for continuous daily cycles of 12 "high" hours of 45 °C and 90% RH, and 12 "low" hours of 25 °C and 20% RH. Samples were analyzed at varying intervals of 14, 24, 36, 43, and 54 days. At each aging interval, crystallographic changes were measured via powder X-ray diffraction coupled with whole pattern fitting for quantitative analysis. Morphologic effects were studied via scanning electron microscopy and 12-way classification via machine learning. While all samples were found to have distinguishing morphologic characteristics (93.2% classification accuracy), α-U3O8 from UO4 had more apparent change with increasing aging time. Nonetheless, α-U3O8 from AUC was found to hydrate more quickly than α-U3O8 from UO4, which can likely be attributed to its larger surface area and porous starting material morphology.
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6
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Renault E, Jian J, Maurice R, van Stipdonk MJ, Tatosian IJ, Bubas AR, Martens J, Berden G, Oomens J, Gibson JK. Characterization of Uranyl Coordinated by Equatorial Oxygen: Oxo in UO 3 versus Oxyl in UO 3. J Phys Chem A 2021; 125:5544-5555. [PMID: 34138571 DOI: 10.1021/acs.jpca.1c03818] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Uranium trioxide, UO3, has a T-shaped structure with bent uranyl, UO22+, coordinated by an equatorial oxo, O2-. The structure of cation UO3+ is similar but with an equatorial oxyl, O•-. Neutral and cationic uranium trioxide coordinated by nitrates were characterized by collision induced dissociation (CID), infrared multiple-photon dissociation (IRMPD) spectroscopy, and density functional theory. CID of uranyl nitrate, [UO2(NO3)3]- (complex A1), eliminates NO2 to produce nitrate-coordinated UO3+, [UO2(O•)(NO3)2]- (B1), which ejects NO3 to yield UO3 in [UO2(O)(NO3)]- (C1). Finally, C1 associates with H2O to afford uranyl hydroxide in [UO2(OH)2(NO3)]- (D1). IRMPD of B1, C1, and D1 confirms uranyl equatorially coordinated by nitrate(s) along with the following ligands: (B1) radical oxyl O•-; (C1) oxo O2-; and (D1) two hydroxyls, OH-. As the nitrates are bidentate, the equatorial coordination is six in A1, five in B1, four in D1, and three in C1. Ligand congestion in low-coordinate C1 suggests orbital-directed bonding. Hydrolysis of the equatorial oxo in C1 epitomizes the inverse trans influence in UO3, which is uranyl with inert axial oxos and a reactive equatorial oxo. The uranyl ν3 IR frequencies indicate the following donor ordering: O2-[best donor] ≫ O•-> OH-> NO3-.
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Affiliation(s)
- Eric Renault
- CEISAM UMR 6230, CNRS, Université de Nantes, F-44000 Nantes, France
| | - Jiwen Jian
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Rémi Maurice
- SUBATECH, UMR CNRS 6457, IN2P3/IMT Atlantique/Université de Nantes, 4 rue Alfred Kastler, BP 20722, 44307 Nantes Cedex 3, France
| | - Michael J van Stipdonk
- Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, Pennsylvania 15282, United States
| | - Irena J Tatosian
- Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, Pennsylvania 15282, United States
| | - Amanda R Bubas
- Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, Pennsylvania 15282, United States
| | - Jonathan Martens
- Radboud University Nijmegen, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525ED Nijmegen, The Netherlands
| | - Giel Berden
- Radboud University Nijmegen, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525ED Nijmegen, The Netherlands
| | - Jos Oomens
- Radboud University Nijmegen, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525ED Nijmegen, The Netherlands.,van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
| | - John K Gibson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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7
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Lee CW, Kwon YK, Heo J. Local atomic structure of uranium ions and dissolution behavior of iron phosphate glass hosts to immobilize spent nuclear fuel. J Radioanal Nucl Chem 2021. [DOI: 10.1007/s10967-021-07687-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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8
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Hanson A, Schwerdt IJ, Nizinski CA, Lee RN, Mecham NJ, Abbott EC, Heffernan S, Olsen A, Klosterman MR, Martinson S, Brenkmann A, McDonald LW. Impact of Controlled Storage Conditions on the Hydrolysis and Surface Morphology of Amorphous-UO 3. ACS OMEGA 2021; 6:8605-8615. [PMID: 33817521 PMCID: PMC8015116 DOI: 10.1021/acsomega.1c00435] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 03/02/2021] [Indexed: 06/12/2023]
Abstract
The hydration and morphological effects of amorphous (A)-UO3 following storage under varying temperature and relative humidity have been investigated. This study provides valuable insight into U-oxide speciation following aging, the U-oxide quantitative morphological data set, and, overall, the characterization of nuclear material provenance. A-UO3 was synthesized via the washed uranyl peroxide synthetic route and aged based on a 3-factor circumscribed central composite design of experiment. Target aging times include 2.57, 7.00, 14.0, 21.0, and 25.4 days, temperatures of 5.51, 15.0, 30.0, 45.0, and 54.5 °C, and relative humidities of 14.2, 30.0, 55.0, 80.0, and 95.8% were examined. Following aging, crystallographic changes were quantified via powder X-ray diffraction and an internal standard Rietveld refinement method was used to confirm the hydration of A-UO3 to crystalline schoepite phases. The particle morphology from scanning electron microscopy images was quantified using both the Morphological Analysis of MAterials software and machine learning. Results from the machine learning were processed via agglomerative hierarchical clustering analysis to distinguish trends in morphological attributes from the aging study. Significantly hydrated samples were found to have a much larger, plate-like morphology in comparison to the unaged controls. Predictive modeling via a response surface methodology determined that while aging time, temperature, and relative humidity all have a quantifiable effect on A-UO3 crystallographic and morphological changes, relative humidity has the most significant impact.
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9
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Pastoor KJ, Kemp RS, Jensen MP, Shafer JC. Progress in Uranium Chemistry: Driving Advances in Front-End Nuclear Fuel Cycle Forensics. Inorg Chem 2021; 60:8347-8367. [PMID: 33619961 DOI: 10.1021/acs.inorgchem.0c03390] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The front-end of the nuclear fuel cycle encompasses several chemical and physical processes used to acquire and prepare uranium for use in a nuclear reactor. These same processes can also be used for weapons or nefarious purposes, necessitating the need for technical means to help detect, investigate, and prevent the nefarious use of nuclear material and nuclear fuel cycle technology. Over the past decade, a significant research effort has investigated uranium compounds associated with the front-end of the nuclear fuel cycle, including uranium ore concentrates (UOCs), UF4, UF6, and UO2F2. These efforts have furthered uranium chemistry with an aim to expand and improve the field of nuclear forensics. Focus has been given to the morphology of various uranium compounds, trace elemental and chemical impurities in process samples of uranium compounds, the degradation of uranium compounds, particularly under environmental conditions, and the development of improved or new techniques for analysis of uranium compounds. Overall, this research effort has identified relevant chemical and physical characteristics of uranium compounds that can be used to help discern the origin, process history, and postproduction history for a sample of uranium material. This effort has also identified analytical techniques that could be brought to bear for nuclear forensics purposes. Continued research into these uranium compounds should yield additional relevant chemical and physical characteristics and analytical approaches to further advance front-end nuclear fuel cycle forensics capabilities.
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Affiliation(s)
- Kevin J Pastoor
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States
| | - R Scott Kemp
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Mark P Jensen
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States.,Nuclear Science and Engineering Program, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Jenifer C Shafer
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States.,Nuclear Science and Engineering Program, Colorado School of Mines, Golden, Colorado 80401, United States
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10
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Pastoor KJ, Robinson SL, Greenwell RA, Quintero Hilsaca CV, Shafer JC, Jensen MP. Understanding uranium oxide hardening during prolonged storage. RADIOCHIM ACTA 2020. [DOI: 10.1515/ract-2020-0044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Uranium ore concentrates (UOCs), the product of uranium mining and milling, are primarily comprised of uranium oxide (U3O8 and UO2) or peroxide (UO4·4H2O and UO4·2H2O) compounds. Following production, UOCs are typically placed in storage until they are converted to uranium hexafluoride (UF6) at a uranium conversion facility. In this study, the chemical changes responsible for an interesting hardening phenomenon observed in UOCs stored for prolonged periods was investigated to understand underlying causes. Powder X-ray diffraction and thermogravimetric analysis were used to characterize free-flowing and hardened UOC samples and revealed the hardened material had undergone hydration and oxidation as indicated by increased moisture content and the presence of metaschoepite [(UO2)4O(OH)6](H2O)5 and/or schoepite [(UO2)4O(OH)6](H2O)6. Additionally, an aging study found metaschoepite in UOCs after 3 months exposure to a high relative humidity environment. The same study found agglomerated, but not fully hardened, material in nearly all aged UOCs samples. These results suggest metaschoepite and schoepite are indicative of UOCs exposed to elevated levels of H2O during storage. Lastly, a drying/calcining study of hardened U3O8 material demonstrated a means of remediation and identified an intermediate compound of potential interest, dehydrated schoepite. Dehydrated schoepite results from heating metaschoepite or schoepite between 100 and 300 °C and indicates partial reversal of hardened U3O8 to its original condition.
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Affiliation(s)
- Kevin J. Pastoor
- Department of Chemistry , Colorado School of Mines , Golden , CO 80401 , USA
| | | | | | | | - Jenifer C. Shafer
- Department of Chemistry , Colorado School of Mines , Golden , CO 80401 , USA
| | - Mark P. Jensen
- Department of Chemistry , Nuclear Science and Engineering Program , Colorado School of Mines , Golden , CO 80401 , USA
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