Determination of Stokes Shape Factor for Single Particles and Agglomerates

Matyáš, Josef; Schaible, Micah J.; Vienna, John D.

doi:10.1002/9781118144527.ch19

“…This is because spinel crystals have high melting temperature, high density, and can form in large size (up to 500 μm) . These crystals, once formed, are difficult to dissolve (unless an elevated melting temperature is used), causing blocking the melter discharge channel during the vitrification process . Therefore, a better understanding of the glass‐spinel crystal interfacial structure and behaviors will help to provide insights on the process and thermodynamic conditions of spinel crystal formation, as well as measures to solve this problem in nuclear waste glass processing …”

Section: Introductionmentioning

confidence: 99%

Local ordering and interfacial structure between spinel crystal and aluminosilicate glasses from molecular dynamics simulations

Sun

¹

,

Du

²

2018

Int J of Appl Glass Sci

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Molecular dynamics simulations were performed to investigate the interfaces of soda magnesia aluminosilicate glass and MgAl2O4 spinel crystals. The glass structures were first generated and characterized. It was found that the glass‐forming network consists of fourfold coordinated [SiO4] and [AlO4] tetrahedra connected through corner sharing with Na+ and Ca2+ acting as modifiers or charge compensators. The glass and crystal interfaces were then constructed on low energy spinel surfaces with special measures to ensure two natural interfaces. The interfacial structures were characterized by z‐density profile, pair distribution function and coordination number analysis. The results show that there exist local ordering on the glass side and preferential adsorption of specific cation near the interface. Cation coordination analyses showed that aluminum ions changed from mainly fourfold coordination in the glass to five and sixfold coordination near the interface suggesting a gradual change in structural role of aluminum from the glass to the crystal. The ordering and segregation of cations, as well as change in aluminum coordination, at the glass/crystal interface strongly suggest that the ordered crystal structure influence the atom distribution and local structure of the adjacent glasses and this ordering can be the initial stage of nucleation or crystal growth.

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“…A significant amount of crystal settling data has been generated in recent studies. [8][9][10][11][12][13][14] However, there is literature available on the settling behavior of crystals as observed in research-, pilot-, and full-scale melter tests that needs to be reviewed and summarized. A thorough literature review will include descriptions of different methodologies for measuring crystal precipitation, settling, and accumulation in molten glasses.…”

Section: Crystal Settling Studies Literature Reviewmentioning

confidence: 99%

Road Map for Development of Crystal-Tolerant High Level Waste Glasses

Matyáš¹,

Vienna²,

Peeler³

et al. 2014

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The U.S. Department of Energy (DOE) is building a Tank Waste Treatment and Immobilization Plant (WTP) at the Hanford Site in Washington to remediate 55 million gallons of radioactive waste that is being temporarily stored in 177 underground tanks. Efforts are being made to increase the loading of Hanford tank wastes in glass while meeting melter lifetime expectancies and process, regulatory, and product quality requirements. This road map guides the research and development for formulation and processing of crystaltolerant glasses, identifying near-and long-term activities that need to be completed over the period from 2014 to 2019. The primary objective is to maximize waste loading for Hanford waste glasses without jeopardizing melter operation by crystal accumulation in the melter or melter discharge riser. The potential applicability to the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF) will also be addressed in this road map.

show abstract

“…A significant amount of crystal settling data has been generated in recent studies. [8][9][10][11][12][13][14] However, there is literature available on the settling behavior of crystals as observed in research-, pilot-, and full-scale melter tests that needs to be reviewed and summarized. A thorough literature review will include descriptions of different methodologies for measuring crystal precipitation, settling, and accumulation in molten glasses.…”

Section: Crystal Settling Studies Literature Reviewmentioning

confidence: 99%

Road Map for Development of Crystal-Tolerant High Level Waste Glasses

Fox¹,

Peeler²,

Herman³

2014

0

View full text Add to dashboard Cite

The U.S. Department of Energy (DOE) is building a Tank Waste Treatment and Immobilization Plant (WTP) at the Hanford Site in Washington to remediate 55 million gallons of radioactive waste that is being temporarily stored in 177 underground tanks. Efforts are being made to increase the loading of Hanford tank wastes in glass while meeting melter lifetime expectancies and process, regulatory, and product quality requirements. This road map guides the research and development for formulation and processing of crystaltolerant glasses, identifying near-and long-term activities that need to be completed over the period from 2014 to 2019. The primary objective is to maximize waste loading for Hanford waste glasses without jeopardizing melter operation by crystal accumulation in the melter or melter discharge riser. The potential applicability to the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF) will also be addressed in this road map.

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Determination of Stokes Shape Factor for Single Particles and Agglomerates

Cited by 11 publications

References 9 publications

Local ordering and interfacial structure between spinel crystal and aluminosilicate glasses from molecular dynamics simulations

Local ordering and interfacial structure between spinel crystal and aluminosilicate glasses from molecular dynamics simulations

Road Map for Development of Crystal-Tolerant High Level Waste Glasses

Road Map for Development of Crystal-Tolerant High Level Waste Glasses

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