1
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Estevenon P, Barral T, Avallone A, Jeffredo M, De La Hos A, Strzelecki A, Le Goff X, Szenknect S, Kvashnina K, Moisy P, Podor R, Guo X, Dacheux N. Hydrothermal synthesis of (Zr,U)SiO 4: an efficient pathway to incorporate uranium into zircon. Dalton Trans 2024; 53:13782-13794. [PMID: 39101436 DOI: 10.1039/d4dt01604a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/06/2024]
Abstract
The preparation of synthetic (Zr,U)SiO4 solid solution is challenging, as the conventional high-temperature solid-state method limits the solubility of uranium (4 ± 1 mol%) in the orthosilicate phase due to its thermodynamic instability. However, these compounds are of great interest as a result of (Zr,U)SiO4 solid solutions, with uranium contents exceeding this concentration, being observed as corium phases formed during nuclear accidents. It has been identified that hydrothermal synthesis pathways can be used for the formation of the metastable phase, such as USiO4. The investigation carried out in this study has indeed led to the confirmation of metastable (Zr,U)SiO4 compounds with high uranium contents being formed. It was found that (Zr,U)SiO4 forms a close-to-ideal solid solution with uranium loading of up to 60 mol% by means of hydrothermal treatment for 7 days at 250 °C, at pH = 3 and starting from an equimolar reactant concentration equal to 0.2 mol L-1. A purification procedure was developed to obtain pure silicate compounds. After purification, these compounds were found to be stable up to 1000 °C under an inert atmosphere (argon). The characterisation methods used to explore the synthesis and thermal stability included powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) and Raman spectroscopies, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA).
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Affiliation(s)
- Paul Estevenon
- CEA, DES, ISEC, DMRC, Univ Montpellier, Marcoule, France
| | - Thomas Barral
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Bagnols-sur-Cèze, France.
| | - Arthur Avallone
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Bagnols-sur-Cèze, France.
| | - Mateo Jeffredo
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Bagnols-sur-Cèze, France.
| | - Alexis De La Hos
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Bagnols-sur-Cèze, France.
| | - Andrew Strzelecki
- Department of Chemistry, Washington State University, Pullman, Washington 99164, USA
- Alexandra Navrotsky Institute for Experimental Thermodynamics, Washington State University, Pullman, Washington 99164, USA
- Materials Science and Engineering, Washington State University, Pullman, Washington 99164, USA
| | - Xavier Le Goff
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Bagnols-sur-Cèze, France.
| | | | - Kristina Kvashnina
- Helmholtz Zentrum Dresden Rossendorf (HZDR), Institute of Resource Ecology, 01314 Dresden, Germany
- The Rossendorf Beamline at ESRF-The European Synchrotron, 38043 Grenoble, Cedex 9, France
| | - Philippe Moisy
- CEA, DES, ISEC, DMRC, Univ Montpellier, Marcoule, France
| | - Renaud Podor
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Bagnols-sur-Cèze, France.
| | - Xiaofeng Guo
- Department of Chemistry, Washington State University, Pullman, Washington 99164, USA
- Alexandra Navrotsky Institute for Experimental Thermodynamics, Washington State University, Pullman, Washington 99164, USA
- Materials Science and Engineering, Washington State University, Pullman, Washington 99164, USA
| | - Nicolas Dacheux
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Bagnols-sur-Cèze, France.
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2
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Neumann A, Kahlenberg V, Lerche I, Stöber S, Pöllmann H. Synthesis and Characterization of Single Crystal Zircon-Hafnon Zr (1-x)Hf (x)SiO 4 Solid Solutions and the Comparison with the Reaction Products of a TEOS-Based Hydrothermal Route. ACS OMEGA 2024; 9:15781-15803. [PMID: 38617697 PMCID: PMC11007697 DOI: 10.1021/acsomega.3c06960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 03/06/2024] [Accepted: 03/08/2024] [Indexed: 04/16/2024]
Abstract
Two synthesis routes of the zircon-hafnon solid solution series were carried out. The high-temperature route uses the growth of single crystals via a flux mixture that has been cooled down slowly from 1400 °C over 4 weeks. The reaction products were colorless and idiomorphic without byproducts. The hydrothermal tetraethoxysilane (TEOS)-based route represents the low-temperature method at 200 °C for approximately 7 days. The hydrothermal route yielded a white powder and scanning electron microscopy analysis thereof did not reveal any specific idiomorphic properties. However, the synthesis also featured some byproducts besides the zircon-hafnon solid solutions. Thermogravimetric analysis coupled with differential scanning calorimetry, and mass spectroscopy indicated, that hydrothermal reaction products feature the presence of organic residues originating from the starting materials. However, a specific dependency on the hafnium content could not be observed due to the data scatter. Infrared (IR) analysis revealed the presence of Zr/Hf-oxides. The structural characterization demonstrated that properties change constantly with the hafnium amount, however, gradual variations of some properties related to the composition of the solid solution series depend in part on the synthesis route, considering the c/a ratio and IR modes. Furthermore, analyses of the single crystals by Raman spectroscopy and μXRF suggested a nonequilibrated crystal growth based on the starting composition.
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Affiliation(s)
- Andreas Neumann
- Institute
of Geoscience and Geography, Martin-Luther-University
Halle-Wittenberg, Von-Seckendorff-Platz 3, D-06120 Halle (Saale), Germany
| | - Volker Kahlenberg
- Institute
of Mineralogy and Petrography, University
of Innsbruck, Innrain 52, A-6020 Innsbruck, Austria
| | - Ian Lerche
- Institute
of Geoscience and Geography, Martin-Luther-University
Halle-Wittenberg, Von-Seckendorff-Platz 3, D-06120 Halle (Saale), Germany
| | - Stefan Stöber
- Institute
of Geoscience and Geography, Martin-Luther-University
Halle-Wittenberg, Von-Seckendorff-Platz 3, D-06120 Halle (Saale), Germany
| | - Herbert Pöllmann
- Institute
of Geoscience and Geography, Martin-Luther-University
Halle-Wittenberg, Von-Seckendorff-Platz 3, D-06120 Halle (Saale), Germany
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3
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Zhao X, Strzelecki AC, Dacheux N, Qi L, Guo X. Phonon softening induced phase transition of CeSiO 4: a density functional theory study. Dalton Trans 2024; 53:6224-6233. [PMID: 38488116 DOI: 10.1039/d4dt00179f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Density functional theory plus Hubbard U (DFT+U) methodology was used to calculate the structures and energetic landscapes of CeSiO4, including its stetindite and scheelite phases from ambient pressure to ∼24 GPa. To ensure accurate simulations of the high-pressure structures, assessments of strain-stress methods and stress-strain methods were conducted in prior, with the former found to have a better agreement with the experimental result. From DFT calculations the equation of states (EOS) of both stetindite and scheelite were further obtained, with the fitted bulk moduli being 182(2) GPa and 190.0(12) GPa, respectively. These results were found to be consistent with the experimental values of 177(5) GPa and 222(40) GPa. Furthermore, the calculated energetics suggest that the stetindite structure is more thermodynamically stable than the scheelite structure at a pressure lower than 8.35 GPa. However, the stetindite → scheelite phase transition was observed experimentally at a much higher pressure of ∼15 GPa. A further phonon spectra investigation by the density functional perturbation theory (DFPT) indicated the Eg1 mode is being softened with pressure and becomes imaginary after 12 GPa, which is a sign of the lattice instability. Consequently, it was concluded that the stetindite → scheelite transition is predominantly initiated by the lattice instability under high-pressure.
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Affiliation(s)
- Xiaodong Zhao
- Department of Chemistry, Washington State University, Pullman, Washington, 99164, USA.
| | - Andrew C Strzelecki
- School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington, 99164, USA
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA
| | - Nicolas Dacheux
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule, Bagnols sur Cèze, 30207, France
| | - Liang Qi
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan, 48109, USA.
| | - Xiaofeng Guo
- Department of Chemistry, Washington State University, Pullman, Washington, 99164, USA.
- School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington, 99164, USA
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4
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Reece ME, Li J, Strzelecki AC, Wen J, Zhang Q, Guo X. Surface thermodynamics of yttrium titanate pyrochlore nanomaterials. NANOSCALE 2024; 16:5421-5432. [PMID: 38385242 DOI: 10.1039/d3nr05605h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Nanocrystalline pyrochlore materials have been investigated for their enhanced radiation tolerance as ceramic nuclear waste hosts. In this work, we study the thermodynamic driving force of nano-scale materials for radiation resistance. The size dependent thermodynamic properties of a series of Y2Ti2O7 nanoparticles were investigated. Samples were synthesized by a sol-gel method and characterized by synchrotron X-ray diffraction, BET analysis, and thermogravimetric analysis. The surface and interface enthalpies of Y2Ti2O7 were determined by high temperature oxide melt drop solution calorimetry to be 4.07 J m-2 and 3.04 J m-2, respectively. The experimentally obtained surface energy is in good agreement with computationally derived average surface energies for yttrium and other rare-earth titanate pyrochlores. Theoretical links between nanoparticle stability, surface energy, and radiation resistance of pyrochlore materials were then explored.
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Affiliation(s)
- Margaret E Reece
- Department of Chemistry, Washington State University, Pullman, WA 99164, USA.
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Jiahong Li
- Department of Chemistry, Washington State University, Pullman, WA 99164, USA.
| | - Andrew C Strzelecki
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
- The School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164, USA
| | - Juan Wen
- School of Materials and Energy, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Qiang Zhang
- Department of Chemistry, Washington State University, Pullman, WA 99164, USA.
| | - Xiaofeng Guo
- Department of Chemistry, Washington State University, Pullman, WA 99164, USA.
- The School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164, USA
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5
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Strzelecki AC, Cockreham CB, Parker SS, Mann SC, Lhermitte C, Wu D, Guo X, Monreal M, Jackson JM, Mitchell J, Boukhalfa H, Xu H. A new methodology for measuring the enthalpies of mixing and heat capacities of molten chloride salts using high temperature drop calorimetry. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:014103. [PMID: 38236299 DOI: 10.1063/5.0144910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 12/12/2023] [Indexed: 01/19/2024]
Abstract
Molten salt reactors (MSRs) are a promising alternative to conventional nuclear reactors as they may offer more efficient fuel utilization, lower waste generation, and improved safety. The state of knowledge of the properties of liquid salts is far from complete. In order to develop the MSR concept, it is essential to develop a fundamental understanding of the thermodynamic properties, including the heat capacities (Cp) and enthalpies of mixing (ΔHmix), of molten salts at MSR operating conditions. Historically, the Cp values of molten salts were determined by drop-calorimetry or differential scanning calorimetry, whereas their ΔHmix values were typically measured using specialized high temperature calorimeters. In this work, a new methodology for measuring both the Cp and the ΔHmix of molten chloride salts was developed. This novel method involves sealing a chloride salt sample in a nickel capsule and performing conventional transposed temperature drop calorimetry using a commercially available Setaram AlexSYS-800 Tian-Calvet twin microcalorimeter. This methodology may be applied to calorimetric measurements of more complex salt mixtures, especially mixtures containing actinides and fission products.
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Affiliation(s)
- Andrew C Strzelecki
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
- Alexandra Navrotsky Institute for Experimental Thermodynamics, Washington State University, Pullman, Washington 99164, USA
- Materials Science and Engineering Program, Washington State University, Pullman, Washington 99164, USA
- Department of Chemistry, Washington State University, Pullman, Washington 99164, USA
| | - Cody B Cockreham
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
- Alexandra Navrotsky Institute for Experimental Thermodynamics, Washington State University, Pullman, Washington 99164, USA
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington 99164, USA
| | - S Scott Parker
- Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Shane C Mann
- Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Charles Lhermitte
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Di Wu
- Alexandra Navrotsky Institute for Experimental Thermodynamics, Washington State University, Pullman, Washington 99164, USA
- Materials Science and Engineering Program, Washington State University, Pullman, Washington 99164, USA
- Department of Chemistry, Washington State University, Pullman, Washington 99164, USA
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington 99164, USA
| | - Xiaofeng Guo
- Alexandra Navrotsky Institute for Experimental Thermodynamics, Washington State University, Pullman, Washington 99164, USA
- Materials Science and Engineering Program, Washington State University, Pullman, Washington 99164, USA
- Department of Chemistry, Washington State University, Pullman, Washington 99164, USA
| | - Marisa Monreal
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J Matt Jackson
- Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Jeremy Mitchell
- Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Hakim Boukhalfa
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Hongwu Xu
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
- School of Molecular Sciences and Center for Materials of the Universe, Arizona State University, Tempe, Arizona 85287, USA
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6
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Strzelecki AC, Wang G, Hickam SM, Parker SS, Batrice R, Jackson JM, Conroy NA, Mitchell JN, Andersson DA, Monreal MJ, Boukhalfa H, Xu H. In Situ High-Temperature Raman Spectroscopy of UCl 3: A Combined Experimental and Theoretical Study. Inorg Chem 2023; 62:18724-18731. [PMID: 37917811 DOI: 10.1021/acs.inorgchem.3c03139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2023]
Abstract
Uranium trichloride (UCl3) has received growing interest for its use in uranium-fueled molten salt reactors and in the pyrochemical processing of used fuel. In this paper, we report for the first time the experimentally determined Raman spectra of UCl3, at both ambient condition and in situ high temperatures up to 871 K. The frequencies of five of the Raman-active vibrational modes (vi) of UCl3 exhibit a negative temperature derivative ((∂νi/∂T)P) with increasing temperature. This red-shift behavior is likely due to the elongation of U-Cl bonds. The average isobaric mode Grüneisen parameter (γiP = 0.91 ± 0.02) of UCl3 was determined through use of the coefficient of thermal expansion published in Vogel et al. (2021) and the (∂νi/∂T)P values determined in this study. These results are in general agreement with those calculated here by density functional theory (DFT+U). Finally, a comparison of the ambient band positions of UCl3 to those of isostructural lanthanide (La-Eu) and actinide chlorides (Am-Cf) has been made.
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Affiliation(s)
- Andrew C Strzelecki
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Materials Science Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Gaoxue Wang
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Sarah M Hickam
- Materials Science Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - S Scott Parker
- Materials Science Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Sigma Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Rami Batrice
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - J Matt Jackson
- Materials Science Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Nathan A Conroy
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Jeremy N Mitchell
- Materials Science Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - David A Andersson
- Materials Science Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Marisa J Monreal
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Hakim Boukhalfa
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Hongwu Xu
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- School of Molecular Sciences and Center for Materials of the Universe, Arizona State University, Tempe, Arizona 85287, United States
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7
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Zhao X, Wang W, Teng Y, Li Y, Ma X, Liu Y, Ahuja R, Luo W, Zhang Z. Incorporation of Th 4+ and Sr 2+ into Rhabdophane/Monazite by Wet Chemistry: Structure and Phase Stability. Inorg Chem 2023; 62:15605-15615. [PMID: 37695943 DOI: 10.1021/acs.inorgchem.3c02253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2023]
Abstract
Rhabdophane is an important permeable reactive barrier to enrich radionuclides from groundwater and has been envisaged to host radionuclides in the backend of the nuclear fuel cycle. However, understanding of how An4+ and Sr2+ precipitate into rhabdophane by wet chemistry has not been resolved. In this work, Th4+ and Sr2+ incorporation in the rhabdophane/monazite structure as La1-2xSrxThxPO4·nH2O solid solutions is successfully achieved in the acid solution at 90 °C. Some specific issues such as lattice occupation of Th4+ and Sr2+, precipitation reaction kinetics, and crystal growth affected by starting stoichiometry are discussed in detail, along with investigating the chemical stability of La1-2xSrxThxPO4·nH2O precipitations and associated La1-2xSrxThxPO4 monazite. The results reveal that the excess of Sr2+ appears to be a prevailing factor with a suggested initial Sr: Th ≥ 2 to obtain the stability domain of La1-2xSrxThxPO4·nH2O (x = 0∼ 0.1). A rapid ion removal associated with a nucleation process has been observed within 8 h, and Th4+ can be removed more than 98% after 24 h in 0.01 mol/L solutions. From structural energetics based on density functional theory, the lattice occupation of Th4+ and Sr2+ is energetically favorable in nonhydrated lattice sites of [LaO8], although two-thirds of lattice sites are associated with [LaO8·H2O] hydrated sites. Intriguingly, the crystal transformation from rhabdophane to monazite associated with the transformation from [SrO8] to [SrO9] polyhedra can greatly improve the leaching stability of Sr2+.
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Affiliation(s)
- Xiaofeng Zhao
- State Key Laboratory of Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, PR China
- The Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, PR China
- Condensed Matter Theory Group, Materials Theory Division, Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
| | - Weipeng Wang
- The Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, PR China
| | - Yuancheng Teng
- State Key Laboratory of Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, PR China
| | - Yuxiang Li
- State Key Laboratory of Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, PR China
| | - Xue Ma
- State Key Laboratory of Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, PR China
| | - Yang Liu
- China Aerodynamics Research and Development Center, Mianyang 621000, PR China
| | - Rajeev Ahuja
- Condensed Matter Theory Group, Materials Theory Division, Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India
| | - Wei Luo
- Condensed Matter Theory Group, Materials Theory Division, Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
| | - Zhengjun Zhang
- The Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, PR China
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8
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Shelyug A, Rafiuddin MR, Mesbah A, Clavier N, Szenknect S, Dacheux N, Guo X, Navrotsky A. Effect of Annealing on Structural and Thermodynamic Properties of ThSiO 4-ErPO 4 Xenotime Solid Solution. Inorg Chem 2021; 60:12020-12028. [PMID: 34328730 DOI: 10.1021/acs.inorgchem.1c01137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effect of annealing on structural and thermochemical properties of a thorite-xenotime solid solution Th1-xErx(SiO4)1-x(PO4)x was assessed. The samples synthesized at low temperatures and stored at room temperature for 2 years retained their tetragonal structures. This structure was also maintained after heating to 1100 °C. During annealing, the structure lost water and exsolved some thorianite phases. The thermodynamic parameters did not change much after annealing, suggesting that xenotime was not a low-temperature metastable phase but rather a stable structure able to withstand elevated temperatures regardless of the thorium content. The solid solution exhibited subregular behavior with the Margules function W(x) = (73.1 ± 20.1) - (125.7 ± 49.8)·x.
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Affiliation(s)
- Anna Shelyug
- Institute of Solid State Chemistry, Yekaterinburg 620990, Russia
| | | | - Adel Mesbah
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule, Bagnols-sur-Cèze 30207, France.,Institut de Recherches sur la Catalyse et l'Environnement de Lyon, IRCELYON, UMR5256, CNRS, Univ Lyon, Université Lyon 1, 2 Avenue Albert Einstein, Villeurbanne Cedex 69626, France
| | - Nicolas Clavier
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule, Bagnols-sur-Cèze 30207, France
| | - Stéphanie Szenknect
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule, Bagnols-sur-Cèze 30207, France
| | - Nicolas Dacheux
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule, Bagnols-sur-Cèze 30207, France
| | - Xiaofeng Guo
- Department of Chemistry and Alexandra Navrotsky Institute for Experimental Thermodynamics, Washington State University, Pullman, Washington 99164, United States
| | - Alexandra Navrotsky
- School of Molecular Sciences a Center for Materials of the Universe, Arizona State University, Tempe, Arizona 85287, United States
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9
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Strzelecki AC, Barral T, Estevenon P, Mesbah A, Goncharov V, Baker J, Bai J, Clavier N, Szenknect S, Migdisov A, Xu H, Ewing RC, Dacheux N, Guo X. The Role of Water and Hydroxyl Groups in the Structures of Stetindite and Coffinite, MSiO 4 (M = Ce, U). Inorg Chem 2021; 60:718-735. [PMID: 33393766 DOI: 10.1021/acs.inorgchem.0c02757] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Orthosilicates adopt the zircon structure types (I41/amd), consisting of isolated SiO4 tetrahedra joined by A-site metal cations, such as Ce and U. They are of significant interest in the fields of geochemistry, mineralogy, nuclear waste form development, and material science. Stetindite (CeSiO4) and coffinite (USiO4) can be formed under hydrothermal conditions despite both being thermodynamically metastable. Water has been hypothesized to play a significant role in stabilizing and forming these orthosilicate phases, though little experimental evidence exists. To understand the effects of hydration or hydroxylation on these orthosilicates, in situ high-temperature synchrotron and laboratory-based X-ray diffraction was conducted from 25 to ∼850 °C. Stetindite maintains its I41/amd symmetry with increasing temperature but exhibits a discontinuous expansion along the a-axis during heating, presumably due to the removal of water confined in the [001] channels, which shrink against thermal expansion along the a-axis. Additional in situ high-temperature Raman and Fourier transform infrared spectroscopy also confirmed the presence of the confined water. Coffinite was also found to expand nonlinearly up to 600 °C and then thermally decompose into a mixture of UO2 and SiO2. A combination of dehydration and dehydroxylation is proposed for explaining the thermal behavior of coffinite synthesized hydrothermally. Additionally, we investigated high-temperature structures of two coffinite-thorite solid solutions, uranothorite (UxTh1-xSiO4), which displayed complex variations in composition during heating that was attributed to the negative enthalpy of mixing. Lastly, for the first time, the coefficients of thermal expansion of CeSiO4, USiO4, U0.46Th0.54SiO4, and U0.9Th0.1SiO4 were determined to be αV = 14.49 × 10-6, 14.29 × 10-6, 17.21 × 10-6, and 17.23 × 10-6 °C-1, respectively.
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Affiliation(s)
- Andrew C Strzelecki
- Department of Chemistry, Washington State University, Pullman 99164, Washington, United States.,Alexandra Navrotsky Institute for Experimental Thermodynamics, Washington State University, Pullman 99164, Washington, United States.,Materials Science and Engineering Program, Washington State University, Pullman 99164, Washington, United States
| | - Thomas Barral
- Department of Chemistry, Washington State University, Pullman 99164, Washington, United States.,Alexandra Navrotsky Institute for Experimental Thermodynamics, Washington State University, Pullman 99164, Washington, United States.,ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule 30207, Bagnols sur Cèze, France
| | - Paul Estevenon
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule 30207, Bagnols sur Cèze, France.,CEA, DES, ISEC, DMRC, Univ Montpellier, Site de Marcoule 30207, France
| | - Adel Mesbah
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule 30207, Bagnols sur Cèze, France
| | - Vitaliy Goncharov
- Department of Chemistry, Washington State University, Pullman 99164, Washington, United States.,Alexandra Navrotsky Institute for Experimental Thermodynamics, Washington State University, Pullman 99164, Washington, United States.,Materials Science and Engineering Program, Washington State University, Pullman 99164, Washington, United States.,Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos 87545, New Mexico, United States
| | - Jason Baker
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos 87545, New Mexico, United States
| | - Jianming Bai
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton 11973, New York, United States
| | - Nicolas Clavier
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule 30207, Bagnols sur Cèze, France
| | - Stephanie Szenknect
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule 30207, Bagnols sur Cèze, France
| | - Artaches Migdisov
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos 87545, New Mexico, United States
| | - Hongwu Xu
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos 87545, New Mexico, United States
| | - Rodney C Ewing
- Department of Geological Sciences, Stanford University, Stanford 94305, California, United States
| | - Nicolas Dacheux
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule 30207, Bagnols sur Cèze, France
| | - Xiaofeng Guo
- Department of Chemistry, Washington State University, Pullman 99164, Washington, United States.,Alexandra Navrotsky Institute for Experimental Thermodynamics, Washington State University, Pullman 99164, Washington, United States.,Materials Science and Engineering Program, Washington State University, Pullman 99164, Washington, United States
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