Rare-earth silicate crystallization in borosilicate glasses: Effect on structural and chemical durability properties

Nicoleau, Elodie; Angeli, Frédéric; Schuller, S.; Charpentier, Thibault; Jollivet, Patrick; Moskura, Mélanie

doi:10.1016/j.jnoncrysol.2016.02.003

Cited by 37 publications

(20 citation statements)

References 58 publications

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“…Unfortunately, the NMR sensitive isotope 17 O does not present favorable NMR characteristics: its low natural abundance (0.037%) thus requires 17 O enrichment, and its 5/2 spin requires special NMR sequences to provide spectra with sufficient resolution. While 17 O has been widely used to analyze the structure of borosilicate-based glasses [65][66][67][68][69][70], there is, to our knowledge, only one paper about 17 O NMR on enriched borophosphate glasses [26]. However, this paper from 2005 clearly showed the possibility of separating bridging P-O-P and P-O-B oxygens by using MQ-MAS NMR experiments [49] and there is no doubt that conducting such a study with the high field NMR machines and the correlation NMR sequences now available would provide a very interesting set of data that would shed new light onto the borophosphate network organization.…”

Section: Discussionmentioning

confidence: 99%

Solid State NMR: A Powerful Tool for the Characterization of Borophosphate Glasses

2020

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This review will show how solid state nuclear magnetic resonance (NMR) has contributed to a better understanding of the borophosphate glass structure. Over the last fifteen years, 1D and 2D magic angle spinning (MAS)-NMR has been used to produce key information about both local and medium range organization in this type of glass. After a brief presentation on borophosphate glasses, the paper will focus on the description of the local order of phosphate and borate species obtained by 1D 31P-and 11B-MAS-NMR experiments, with a special emphasis on the improvements obtained at high magnetic fields on the borate speciation description. The last part of this review will show how correlation NMR provided new insights into the intermediate length scale order. Special attention will be paid to the quantitative data retrieved from 11B/31P REDOR-based NMR sequences and to the qualitative connectivity schemes observed on the 2D 11B/31P maps edited with the heteronuclear multiple quantum coherence (HMQC) NMR techniques.

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Section: Discussionmentioning

confidence: 99%

Solid State NMR: A Powerful Tool for the Characterization of Borophosphate Glasses

2020

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“…Before we discuss the impact of Nd2O3 on the solubility of MoO3 in the aluminoborosilicate glasses under investigation, it is important to understand the structural role of Nd2O3 in these glasses as it has direct implications on the solubility of MoO3. The structural coordination of rare-earth cations in alkali/alkaline-earth aluminoborosilicate glasses has been studied in detail primarily by researchers from two countries -USA, 33,34,[52][53][54][55][56][57][58][59] and France 40,[60][61][62][63][64][65] owing to their high relevance in the field of nuclear waste immobilization. The rare-earth free per-alkaline glasses with Na2Oex/B2O3 > 0.5, for example, 60SiO2•15B2O3•20Na2O•5Al2O3 (mol.%), 52,58 have been shown to be homogeneous.…”

Section: Impact Of Nd2o3 On Moo3 Solubility In Aluminoborosilicate Glmentioning

confidence: 99%

Compositional Dependence of Solubility/Retention of Molybdenum Oxides in Aluminoborosilicate-Based Model Nuclear Waste Glasses

et al. 2018

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Molybdenum oxides are an integral component of the high-level waste streams being generated from the nuclear reactors in several countries. Although borosilicate glass has been chosen as the baseline waste form by most of the countries to immobilize these waste streams, molybdate oxyanions (MoO) exhibit very low solubility (∼1 mol %) in these glass matrices. In the past three to four decades, several studies describing the compositional and structural dependence of molybdate anions in borosilicate and aluminoborosilicate glasses have been reported in the literature, providing a basis for our understanding of fundamental science that governs the solubility and retention of these species in the nuclear waste glasses. However, there are still several open questions that need to be answered to gain an in-depth understanding of the mechanisms that control the solubility and retention of these oxyanions in glassy waste forms. This article is focused on finding answers to two such questions: (1) What are the solubility and retention limits of MoO in aluminoborosilicate glasses as a function of chemical composition? (2) Why is there a considerable increase in the solubility of MoO with incorporation of rare-earth oxides (for example, NdO) in aluminoborosilicate glasses? Accordingly, three different series of aluminoborosilicate glasses (compositional complexity being added in a tiered approach) with varying MoO concentrations have been synthesized and characterized for their ability to accommodate molybdate ions in their structure (solubility) and as a glass-ceramic (retention). The contradictory viewpoints (between different research groups) pertaining to the impact of rare-earth cations on the structure of aluminoborosilicate glasses are discussed, and their implications on the solubility of MoO in these glasses are evaluated. A novel hypothesis explaining the mechanism governing the solubility of MoO in rare-earth containing aluminoborosilicate glasses has been proposed.

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“…The usual synthesis protocol for Ca 2 Ln 8 (SiO 4 ) 6 O 2 apatites is a calcination of CaO, Ln 2 O 3 and SiO 2 in appropriate amounts under air above 1673 K (Nicoleau et al, 2016). A trivalent Ln precursor is used, with the same oxidation state as found in the final apatite.…”

Section: Synthesis and Crystallizationmentioning

confidence: 99%

Reinvestigation of the crystal structure of Ca₂Ce₈(SiO₄)₆O₂ apatite by Rietveld refinement

2018

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Rare-earth silicate crystallization in borosilicate glasses: Effect on structural and chemical durability properties

Cited by 37 publications

References 58 publications

Solid State NMR: A Powerful Tool for the Characterization of Borophosphate Glasses

Solid State NMR: A Powerful Tool for the Characterization of Borophosphate Glasses

Compositional Dependence of Solubility/Retention of Molybdenum Oxides in Aluminoborosilicate-Based Model Nuclear Waste Glasses

Reinvestigation of the crystal structure of Ca₂Ce₈(SiO₄)₆O₂ apatite by Rietveld refinement

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Rare-earth silicate crystallization in borosilicate glasses: Effect on structural and chemical durability properties

Cited by 37 publications

References 58 publications

Solid State NMR: A Powerful Tool for the Characterization of Borophosphate Glasses

Solid State NMR: A Powerful Tool for the Characterization of Borophosphate Glasses

Compositional Dependence of Solubility/Retention of Molybdenum Oxides in Aluminoborosilicate-Based Model Nuclear Waste Glasses

Reinvestigation of the crystal structure of Ca2Ce8(SiO4)6O2 apatite by Rietveld refinement

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Reinvestigation of the crystal structure of Ca₂Ce₈(SiO₄)₆O₂ apatite by Rietveld refinement