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Zhang D, Diao X, Wang Y, Xu K, Jin Q, Chen Z, Guo Z. Effect of Si content, pH, electrolyte and fulvic acid on the stability of Th(IV)-silicate colloids. J Radioanal Nucl Chem 2022. [DOI: 10.1007/s10967-022-08703-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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2
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Estevenon P, Causse J, Szenknect S, Welcomme E, Mesbah A, Moisy P, Poinssot C, Dacheux N. In situ study of the synthesis of thorite (ThSiO 4) under environmental representative conditions. Dalton Trans 2020; 49:11512-11521. [PMID: 32840279 DOI: 10.1039/d0dt01790f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Thorite, (ThSiO4) with a zircon type structure, is one of the most abundant natural sources of thorium on Earth. Generally, actinides are known to form nanoparticles in silicate medium, though no direct link between those colloids and the crystalline form of thorite was evidenced until now. Here we show the formation of thorite from colloids and nanocrystalline structures under experimental conditions close to environmental pH and temperature. Through in situ small and wide angle X-ray scattering (SWAXS) measurements, colloids with a few nanometers in size were first evidenced at a low reaction time. These colloids have elongated shapes and finally tend to aggregate after their size has reached 10 nm. Once aggregated, the system goes through a maturation step, ending with the emergence of nanocrystallites as thorite zircon structures. This maturation step is longer when the reaction temperature is decreased which highlights the kinetic considerations. These results have potential implications on the paragenesis of Th mineral deposits and also in the behaviour of Th and, by analogy, tetravalent actinides in the environment. The significant characteristics of this work are that Th-silicate colloids were demonstrated at low temperatures and a near neutral pH with long-term stability and a morphology in favor of high mobility in groundwater. If these species are formed in more diluted media, this could be problematic owing to the spreading of Th and, by analogy, other tetravalent actinides in the environment.
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Affiliation(s)
- Paul Estevenon
- ICSM, Univ Montpellier, CEA, CNRS, ENSCM, Bagnols-sur-Cèze, France. and CEA, DES, ISEC, DMRC, Univ Montpellier, Marcoule, France
| | - Jeremy Causse
- ICSM, Univ Montpellier, CEA, CNRS, ENSCM, Bagnols-sur-Cèze, France.
| | | | | | - Adel Mesbah
- ICSM, Univ Montpellier, CEA, CNRS, ENSCM, Bagnols-sur-Cèze, France.
| | - Philippe Moisy
- CEA, DES, ISEC, DMRC, Univ Montpellier, Marcoule, France
| | | | - Nicolas Dacheux
- ICSM, Univ Montpellier, CEA, CNRS, ENSCM, Bagnols-sur-Cèze, France.
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3
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Estevenon P, Welcomme E, Tamain C, Jouan G, Szenknect S, Mesbah A, Poinssot C, Moisy P, Dacheux N. The formation of PuSiO 4 under hydrothermal conditions. Dalton Trans 2020; 49:6434-6445. [PMID: 32355939 DOI: 10.1039/d0dt01183e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Attempts to synthesize plutonium(iv) silicate, PuSiO4, have been made on the basis of results recently reported in the literature for CeSiO4, ThSiO4, and USiO4 under hydrothermal conditions. Although it was not possible to prepare PuSiO4via applying the conditions reported for thorium and uranium, an efficient method of PuSiO4 synthesis was established by applying the conditions optimized for the CeSiO4 system. This method was based on the slow oxidation of plutonium(iii) silicate reactants under hydrothermal conditions at 150 °C in hydrochloric acid (pH = 3-4). These results shed new light on the potential behavior of plutonium in reductive environments, highlighting the representative nature of cerium surrogates when studying plutonium under such conditions and providing some important pieces of information regarding plutonium chemistry in silicate solutions.
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Affiliation(s)
- Paul Estevenon
- CEA, DES, ISEC, DMRC, Univ Montpellier, Marcoule, France and ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule, Bagnols-sur-Cèze, France.
| | | | | | - Gauthier Jouan
- CEA, DES, ISEC, DMRC, Univ Montpellier, Marcoule, France
| | - Stephanie Szenknect
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule, Bagnols-sur-Cèze, France.
| | - Adel Mesbah
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule, Bagnols-sur-Cèze, France.
| | | | - Philippe Moisy
- CEA, DES, ISEC, DMRC, Univ Montpellier, Marcoule, France
| | - Nicolas Dacheux
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule, Bagnols-sur-Cèze, France.
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4
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Ghadiri A, Abdollahy M, Khanchi A, Khalesi MR, Akbari M. Synthesis and Characterization of Thorite Nanoparticles by Hydrothermal Method. RUSS J INORG CHEM+ 2020. [DOI: 10.1134/s0036023619140122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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5
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Colmenero F. Thermodynamic properties of the uranyl carbonate minerals roubaultite, fontanite, widenmannite, grimselite, čejkaite and bayleyite. Inorg Chem Front 2020. [DOI: 10.1039/d0qi01019g] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The thermodynamic properties of six important uranyl carbonate minerals, roubaultite, fontanite, widenmannite, grimselite, čejkaite and bayleyite, are determined as a function of temperature using first principles methods.
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6
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Estevenon P, Welcomme E, Szenknect S, Mesbah A, Moisy P, Poinssot C, Dacheux N. Preparation of CeSiO 4 from aqueous precursors under soft hydrothermal conditions. Dalton Trans 2019; 48:7551-7559. [PMID: 31119248 DOI: 10.1039/c9dt01258c] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Even though CeSiO4 was synthesized one time through a hydrothermal treatment, the conditions leading to its formation remain largely unknown. In order to define the optimized conditions of synthesis, a multiparametric study was developed by varying the pH of the solution, the temperature, and the nature of the reactants and of the complexing ions in solution. This study highlighted that CeSiO4 could not be obtained starting from Ce(iv) reactants. An optimal set of conditions was defined to prepare single phase samples. Pure CeSiO4 was obtained through a hydrothermal treatment at 150 °C using a starting mixture of 1 mol L-1 Ce(iii) nitrate and Na2SiO3 solutions and by adjusting the initial pH to 8. The chemical limitations observed during the synthesis of CeSiO4 suggested that the formation of this phase may result from the slow in situ oxidation of a Ce(iii) silicate complex during the hydrothermal treatment.
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Affiliation(s)
- Paul Estevenon
- CEA, Nuclear Energy Division, CEA Marcoule Research Department of Mining and Fuel Recycling Processes, DMRC, BP 17171, 30207 Bagnols-sur-Cèze, France
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7
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Liu Q, Yin H, Bao H, Yue Z, Diefenbach K, Tang Z, Lin J, Wang JQ. Insights into the new 3d–5f heterometallic quaternary fluorides: Synthesis, crystal structures, spectroscopic properties, and thermodynamic stability. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2018.12.038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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8
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Estevenon P, Welcomme E, Szenknect S, Mesbah A, Moisy P, Poinssot C, Dacheux N. Impact of Carbonate Ions on the Synthesis of ThSiO4 under Hydrothermal Conditions. Inorg Chem 2018; 57:12398-12408. [DOI: 10.1021/acs.inorgchem.8b02146] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Paul Estevenon
- CEA, Nuclear Energy Division, Research Department of Mining and Fuel Recycling Processes, DEN/DMRC, CEA Marcoule, BP 17171, 30207 Bagnols-sur-Cèze, France
- ICSM, CEA, CNRS, ENSCM, Univ Montpellier, Site de Marcoule, Bât.
426, BP 17171, 30207 Bagnols-sur-Cèze, France
| | - Eleonore Welcomme
- CEA, Nuclear Energy Division, Research Department of Mining and Fuel Recycling Processes, DEN/DMRC, CEA Marcoule, BP 17171, 30207 Bagnols-sur-Cèze, France
| | - Stephanie Szenknect
- ICSM, CEA, CNRS, ENSCM, Univ Montpellier, Site de Marcoule, Bât.
426, BP 17171, 30207 Bagnols-sur-Cèze, France
| | - Adel Mesbah
- ICSM, CEA, CNRS, ENSCM, Univ Montpellier, Site de Marcoule, Bât.
426, BP 17171, 30207 Bagnols-sur-Cèze, France
| | - Philippe Moisy
- CEA, Nuclear Energy Division, Research Department of Mining and Fuel Recycling Processes, DEN/DMRC, CEA Marcoule, BP 17171, 30207 Bagnols-sur-Cèze, France
| | - Christophe Poinssot
- CEA, Nuclear Energy Division, Research Department of Mining and Fuel Recycling Processes, DEN/DMRC, CEA Marcoule, BP 17171, 30207 Bagnols-sur-Cèze, France
| | - Nicolas Dacheux
- ICSM, CEA, CNRS, ENSCM, Univ Montpellier, Site de Marcoule, Bât.
426, BP 17171, 30207 Bagnols-sur-Cèze, France
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9
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Estevenon P, Welcomme E, Szenknect S, Mesbah A, Moisy P, Poinssot C, Dacheux N. Multiparametric Study of the Synthesis of ThSiO4 under Hydrothermal Conditions. Inorg Chem 2018; 57:9393-9402. [DOI: 10.1021/acs.inorgchem.8b01390] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Paul Estevenon
- CEA, Nuclear Energy Division, CEA Marcoule, Research Department of Mining and Fuel Recycling Processes, DEN/DMRC, BP 17171, 30207 Bagnols-sur-Cèze, France
| | - Eleonore Welcomme
- CEA, Nuclear Energy Division, CEA Marcoule, Research Department of Mining and Fuel Recycling Processes, DEN/DMRC, BP 17171, 30207 Bagnols-sur-Cèze, France
| | - Stephanie Szenknect
- ICSM, CEA, CNRS, ENSCM, Univ Montpellier, Site de Marcoule,
Bât. 426, BP 17171, 30207 Bagnols-sur-Cèze, France
| | - Adel Mesbah
- ICSM, CEA, CNRS, ENSCM, Univ Montpellier, Site de Marcoule,
Bât. 426, BP 17171, 30207 Bagnols-sur-Cèze, France
| | - Philippe Moisy
- CEA, Nuclear Energy Division, CEA Marcoule, Research Department of Mining and Fuel Recycling Processes, DEN/DMRC, BP 17171, 30207 Bagnols-sur-Cèze, France
| | - Christophe Poinssot
- CEA, Nuclear Energy Division, CEA Marcoule, Research Department of Mining and Fuel Recycling Processes, DEN/DMRC, BP 17171, 30207 Bagnols-sur-Cèze, France
| | - Nicolas Dacheux
- ICSM, CEA, CNRS, ENSCM, Univ Montpellier, Site de Marcoule,
Bât. 426, BP 17171, 30207 Bagnols-sur-Cèze, France
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10
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Zänker H, Weiss S, Hennig C, Brendler V, Ikeda‐Ohno A. Oxyhydroxy Silicate Colloids: A New Type of Waterborne Actinide(IV) Colloids. ChemistryOpen 2016; 5:174-182. [PMID: 27957406 PMCID: PMC5130165 DOI: 10.1002/open.201500207] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 02/26/2016] [Indexed: 11/10/2022] Open
Abstract
At the near-neutral and reducing aquatic conditions expected in undisturbed ore deposits or in closed nuclear waste repositories, the actinides Th, U, Np, and Pu are primarily tetravalent. These tetravalent actinides (AnIV) are sparingly soluble in aquatic systems and, hence, are often assumed to be immobile. However, AnIV could become mobile if they occur as colloids. This review focuses on a new type of AnIV colloids, oxyhydroxy silicate colloids. We herein discuss the chemical characteristics of these colloids and the potential implication for their environmental behavior. The binary oxyhydroxy silicate colloids of AnIV could be potentially more mobile as a waterborne species than the well-known mono-component oxyhydroxide colloids.
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Affiliation(s)
- Harald Zänker
- Institute of Resource EcologyHelmholtz-Zentrum Dresden-RossendorfP.O. Box 51 01 1901314DresdenGermany
| | - Stephan Weiss
- Institute of Resource EcologyHelmholtz-Zentrum Dresden-RossendorfP.O. Box 51 01 1901314DresdenGermany
| | - Christoph Hennig
- Institute of Resource EcologyHelmholtz-Zentrum Dresden-RossendorfP.O. Box 51 01 1901314DresdenGermany
| | - Vinzenz Brendler
- Institute of Resource EcologyHelmholtz-Zentrum Dresden-RossendorfP.O. Box 51 01 1901314DresdenGermany
| | - Atsushi Ikeda‐Ohno
- Institute of Resource EcologyHelmholtz-Zentrum Dresden-RossendorfP.O. Box 51 01 1901314DresdenGermany
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11
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Mesbah A, Szenknect S, Clavier N, Lozano-Rodriguez J, Poinssot C, Den Auwer C, Ewing RC, Dacheux N. Coffinite, USiO4, Is Abundant in Nature: So Why Is It So Difficult To Synthesize? Inorg Chem 2015; 54:6687-96. [PMID: 26145720 DOI: 10.1021/ic502808n] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Coffinite, USiO4, is the second most abundant U(4+) mineral on Earth, and its formation by the alteration of the UO2 in spent nuclear fuel in a geologic repository may control the release of radionuclides to the environment. Despite its abundance in nature, the synthesis and characterization of coffinite have eluded researchers for decades. On the basis of the recent synthesis of USiO4, we can now define the experimental conditions under which coffinite is most efficiently formed. Optimal formation conditions are defined for four parameters: pH, T, heating time, and U/Si molar ratio. The adjustment of pH between 10 and 12 leads probably to the formation of a uranium(IV) hydroxo-silicate complex that acts as a precursor of uranium(IV) silicate colloids and then of coffinite. Moreover, in this pH range, the largest yield of coffinite formation (as compared with those of the two competing byproduct phases, nanometer-scale UO2 and amorphous SiO2) is obtained for 250 °C, 7 days, and 100% excess silica.
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Affiliation(s)
- Adel Mesbah
- †ICSM, UMR 5257 CEA/CNRS/UM/ENSCM, Site de Marcoule-Bât. 426, BP 17171, 30207 Bagnols-sur-Cèze cedex, France
| | - Stephanie Szenknect
- †ICSM, UMR 5257 CEA/CNRS/UM/ENSCM, Site de Marcoule-Bât. 426, BP 17171, 30207 Bagnols-sur-Cèze cedex, France
| | - Nicolas Clavier
- †ICSM, UMR 5257 CEA/CNRS/UM/ENSCM, Site de Marcoule-Bât. 426, BP 17171, 30207 Bagnols-sur-Cèze cedex, France
| | - Janeth Lozano-Rodriguez
- ⊥HZDR, Institute of Resource Ecology, Rossendorf Beamline at ESRF, P.O. Box 220, 38043 Grenoble, France
| | - Christophe Poinssot
- ‡CEA, Nuclear Energy Division, DRCP/DIR, CEA Marcoule, Bât. 400, BP 17171, 30207 Bagnols-sur-Cèze cedex, France
| | - Christophe Den Auwer
- ∥ICN, UMR 7272, Nice Sophia-Antipolis University, 28 av. de Valrose, 06108 Nice cedex 2, France
| | | | - Nicolas Dacheux
- †ICSM, UMR 5257 CEA/CNRS/UM/ENSCM, Site de Marcoule-Bât. 426, BP 17171, 30207 Bagnols-sur-Cèze cedex, France
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12
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Abstract
Coffinite, USiO4, is an important U(IV) mineral, but its thermodynamic properties are not well-constrained. In this work, two different coffinite samples were synthesized under hydrothermal conditions and purified from a mixture of products. The enthalpy of formation was obtained by high-temperature oxide melt solution calorimetry. Coffinite is energetically metastable with respect to a mixture of UO2 (uraninite) and SiO2 (quartz) by 25.6 ± 3.9 kJ/mol. Its standard enthalpy of formation from the elements at 25 °C is -1,970.0 ± 4.2 kJ/mol. Decomposition of the two samples was characterized by X-ray diffraction and by thermogravimetry and differential scanning calorimetry coupled with mass spectrometric analysis of evolved gases. Coffinite slowly decomposes to U3O8 and SiO2 starting around 450 °C in air and thus has poor thermal stability in the ambient environment. The energetic metastability explains why coffinite cannot be synthesized directly from uraninite and quartz but can be made by low-temperature precipitation in aqueous and hydrothermal environments. These thermochemical constraints are in accord with observations of the occurrence of coffinite in nature and are relevant to spent nuclear fuel corrosion.
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Jin GB, Soderholm L. Solid-state syntheses and single-crystal characterizations of three tetravalent thorium and uranium silicates. J SOLID STATE CHEM 2015. [DOI: 10.1016/j.jssc.2014.10.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Zänker H, Hennig C. Colloid-borne forms of tetravalent actinides: a brief review. JOURNAL OF CONTAMINANT HYDROLOGY 2014; 157:87-105. [PMID: 24365396 DOI: 10.1016/j.jconhyd.2013.11.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 11/08/2013] [Accepted: 11/26/2013] [Indexed: 06/03/2023]
Abstract
Tetravalent actinides, An(IV), are usually assumed to be little mobile in near-neutral environmental waters because of their low solubility. However, there are certain geochemical scenarios during which mobilization of An(IV) in a colloid-borne (waterborne) form cannot be ruled out. A compilation of colloid-borne forms of tetravalent actinides described so far for laboratory experiments together with several examples of An(IV) colloids observed in field experiments and real-world scenarios are given. They are intended to be a knowledge base and a tool for those who have to interpret actinide behavior under environmental conditions. Synthetic colloids containing structural An(IV) and synthetic colloids carrying adsorbed An(IV) are considered. Their behavior is compared with the behavior of An(IV) colloids observed after the intentional or unintentional release of actinides into the environment. A list of knowledge gaps as to the behavior of An(IV) colloids is provided and items which need further research are highlighted.
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Affiliation(s)
- Harald Zänker
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 51 01 19, D-01314 Dresden, Germany.
| | - Christoph Hennig
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 51 01 19, D-01314 Dresden, Germany
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Clavier N, Szenknect S, Costin DT, Mesbah A, Poinssot C, Dacheux N. From thorite to coffinite: a spectroscopic study of Th(1-x)U(x)SiO4 solid solutions. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 118:302-307. [PMID: 24055679 DOI: 10.1016/j.saa.2013.08.093] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 08/19/2013] [Accepted: 08/23/2013] [Indexed: 06/02/2023]
Abstract
Coffinite (USiO4), along with Th(1-x)U(x)SiO4 uranothorite solid solutions, are frequently present in reduced economically exploitable uranium ores. They could also control the concentration of uranium in the environment in the case of accidental release from underground radwaste repository. This paper reports for the first time a thorough FTIR and Raman study relative to the Th(1-x)U(x)SiO4 system, including synthetic analogues of thorite and coffinite end-members. Both sets of spectra confirmed the formulation of the samples and allowed to rule out the presence of structural water molecules and/or hydroxyl groups in the coffinite. Also, no characteristic signal of UO2(2+) uranyl ion was recorded, ensuring that uranium was fully incorporated under its tetravalent oxidation state. The variation of the positions corresponding to SiO4 internal vibration modes was then followed versus the chemical composition of the samples. If the FTIR spectra did not revealed any significant shift in the bands position, several Raman modes followed a linear trend as a function of the uranium incorporation rate. On this basis, Raman spectroscopy could be considered as a promising tool for the semi-quantitative determination of chemical composition of uranothorite samples, particularly for those coming from mineral ores. Finally, the data collected for the coffinite end-member, as the first to be obtained on pure synthetic samples, allowed a review of the results previously reported in the literature for this compound.
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Affiliation(s)
- N Clavier
- ICSM, UMR 5257 CEA/CNRS/UM2/ENSCM, Site de Marcoule - Bât. 426, BP 17171, 30207 Bagnols/Cèze cedex, France.
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Labs S, Hennig C, Weiss S, Curtius H, Zänker H, Bosbach D. Synthesis of coffinite, USiO4, and structural investigations of UxTh(1-x)SiO4 solid solutions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 48:854-860. [PMID: 24289534 DOI: 10.1021/es403995b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The miscibility behavior of the USiO4-ThSiO4 system was investigated. The end members and 10 solid solutions UxTh(1-x)SiO4 with x = 0.12-0.92 were successfully synthesized, without formation of other secondary uranium or thorium phases. Lattice parameters of the solid solutions evidently follow Vegard's Law. Investigation of the local structure with EXAFS reveals small differences between the U and Th environment attributed to different atomic radii of the metal atoms but no implications for a miscibility gap. The data provided confirm complete miscibility for the system USiO4-ThSiO4. The structure of the end members was studied in detail with XRD and discussed with special regard to the oxygen positions and the often neglected Si-O bond length. USiO4 could be obtained without UO2 impurities and the lattice parameters derived from Rietveld refinement as c = 6.2606(3) Å and a = 6.9841(3) Å. The Si-O distance in USiO4 appears to be 1.64 Å, which is more reasonable than earlier reported values.
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Affiliation(s)
- Sabrina Labs
- Insitute of Energy and Climate Research (IEK-6), Nuclear Waste Management, Forschungszentrum Jülich GmbH , Wilhelm-Johnen-Straße, 54245 Jülich, Germany
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