Gadolinium solubility in peraluminous borosilicate glasses

Li, Liyu; Li, Hong; Qian, Mingxin; Strachan, Denis M.

doi:10.1016/s0022-3093(00)00441-5

Cited by 26 publications

(10 citation statements)

References 31 publications

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“…For instance, Gasnier et al 33 observed an amorphous phase separation with Nd + B enriched versus Nd + Si enriched phases only when the RE oxide concentration was high (8‐10 mol.% Nd 2 O 3 ). By contrast, studies by Li and co‐workers 86‐89 suggest that RE (La, Nd, and Gd were studied) ions partition first to a borate phase then with increasing concentration to a silicate phase. The compositions described in the current paper have considerably less Al 2 O 3 than the cited studies, but contain other metals requiring charge compensation to dissolve in the glass network (Mo, Zr).…”

Section: Discussionmentioning

confidence: 90%

“…Most studies looking at RE oxide role in glasses are performed with La or Nd, 2,90 while relatively fewer have looked at lower field strength RE cations like Gd 88,89 . In the glasses studied here, the 15B10Gd composition is on the border of a major trend change in crystallization behavior, though it does still form the RE borosilicate crystalline phase.…”

Section: Discussionmentioning

confidence: 94%

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Partitioning of rare earths in multiphase nuclear waste glass‐ceramics

Chen

Marcial

Ahmadzadeh

et al. 2020

Int J of Appl Glass Sci

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Alumino‐borosilicate glass‐ceramics (GCs) containing alkali (Na), alkaline earth (Ca), rare earth (RE) (one of La … Lu, Y), and transition metals (Zr and Mo) were formulated to test the effects of composition and RE cation size on the crystallization of simulated nuclear waste GCs. Eight‐oxide glasses were formulated in the peraluminous ([Na2Oexcess]=[Na2O]‐[Al2O3]‐[ZrO2]<0) region with 10 mol.% RE2O3 and 15 mol.% B2O3. Glasses were melted and quenched, reheated, and slow‐cooled to promote crystallization, and then characterized using quantitative X‐ray diffraction and electron probe microanalysis. Transition metal phases [powellite (Ca,Na,RE)MoO4 and zirconia (Zr,RE)O2 or zircon (Zr,RE)SiO4] always formed, while borosilicate (RE3BSi2O10) or silicate [oxyapatite (RE,Ca,Na)10Si6O26 or keiviite (RE2Si2O7)] plus borate (REBO3) phases also formed, depending on the size of the RE cation and hence its preferred coordination number. All crystalline phases were found to contain RE elements, and often phases incorporated other cations (Zr, Ca, B) which were not nominally part of their pure stoichiometry. These results suggested that the glass formulation and RE size strongly influenced the RE environment in the glass and hence the crystal phases formed. The formation of RE borosilicate, versus separate RE borate and RE silicate phases, also suggested original differences in the glass structure.

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Section: Discussionmentioning

confidence: 90%

Section: Discussionmentioning

confidence: 94%

Partitioning of rare earths in multiphase nuclear waste glass‐ceramics

Chen

Marcial

Ahmadzadeh

et al. 2020

Int J of Appl Glass Sci

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“…The solubility of lanthanides, substantially higher in peraluminous glasses, and their tendency to crystallize, also appear to be strongly dependent on the R P ratio. [8][9][10][11] The potential (i.e., the homogeneity and thermal stability) of peraluminous glasses as HLW conditioning matrices has already been highlighted in a previous study. 15 A candidate composition for long-term studies in contact with aqueous solutions was selected by optimizing its composition as a function of its physico-chemical properties (viscosity, glass transition temperature, density, homogeneity).…”

Section: Introductionmentioning

confidence: 78%

“…[5][6][7] Two composition ranges, both in the SiO 2 -B 2 O 3 -Al 2 O 3 -Na 2 O-CaO-RE 2 O 3 system, have already been explored. [8][9][10][11][12][13][14][15][16] These two domains of composition are defined by the molar oxides R ) with M and M' corresponding to alkaline and alkalineearth elements, respectively. In a peralkaline glass (R P > 0.5), the modifier ions are in excess with respect to the aluminum ions whereas in a peraluminous glass (R P < 0.5), the aluminum ions are in excess.…”

Section: Introductionmentioning

confidence: 99%

Chemical durability of peraluminous glasses for nuclear waste conditioning

Piovesan¹,

Bardez-Giboire²,

Fournier³

et al. 2018

npj Mater Degrad

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For the handling of high level nuclear waste (HLW), new glass formulations with a high waste capacity and an enhanced thermal stability, chemical durability, and processability are under consideration. This study focuses on the durability of peraluminous glasses in the SiO 2-Al 2 O 3-B 2 O 3-Na 2 O-CaO-La 2 O 3 system, defined by an excess of Al 3+ ions compared with the network-modifying cations Na + and Ca 2+. To qualify the behavior of such a peraluminous glass in a geological storage situation, its chemical durability was studied in various environments (pure water, groundwater, and alkaline solutions related to a cement environment) and glass alteration regimes (initial rate, residual rate, and resumption of alteration). The alteration solution was characterized by inductively coupled plasma, and the altered glass by scanning electron microscopy, X-ray diffraction and secondary ion mass spectrometry. A comparative study of the chemical durability of these and reference glasses (ISG and SON68) over all timescales highlights the remarkable properties of the former. While their initial dissolution rate is of the same order as the reference glasses, the gel formed under silica saturation conditions is more passivating, making its dissolution rate at least one order of magnitude lower, while its low alkalinity makes it less susceptible to clayey groundwater and highly alkaline solutions.

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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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Gadolinium solubility in peraluminous borosilicate glasses

Cited by 26 publications

References 31 publications

Partitioning of rare earths in multiphase nuclear waste glass‐ceramics

Partitioning of rare earths in multiphase nuclear waste glass‐ceramics

Chemical durability of peraluminous glasses for nuclear waste conditioning

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

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