Effect of B on Crystallization of Li and Na aluminosilicates - 16323

Conference · Fri Jul 01 04:00:00 EDT 2016

OSTI ID:22838160

Marcial, Jose ^[1]; Kabel, Joey; Saleh, Muad ^[2]; Shaharyar, Yaqoot; Goel, Ashutosh ^[3]; McCloy, John ^[1]

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1. Materials Science and Engineering Program, Washington State University, Pullman, WA 99164 (United States)
2. School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164 (United States)
3. Department of Materials Science and Engineering, Rutgers - The State University of New Jersey, Piscataway, NJ 08854 (United States)

The vitrification of Hanford high-level waste (HLW) requires careful balance of glass-forming additives and nuclear waste components to maximize the waste loading but prevent adverse effects such as crystallization of aluminosilicates upon cooling in canisters. Aluminosilicate crystallization removes chemically durable glass-formers from the melt, leaving behind a residual glass that is enriched in less durable components, such as alkali and boron. In our previous work, it has been shown that the composition of the starting melt has a large influence on the phase and composition of the nucleating crystals, typically nepheline (NaAlSiO{sub 4}) when wastes are simultaneously high in Na and Al. Chemical partitioning allows for additional crystallization in the residual glass. Interestingly, in HLW glass the primary phases to form are those of sodium or lithium aluminosilicates despite the presence of boron, a common additive known to reduce crystallization and lower viscosity and melting point. In this work, we seek to better understand aluminosilicate crystallization in the presence of boron. Twelve glasses were prepared along the tie lines of NaAlSiO{sub 4}-NaBSiO{sub 4} and LiAlSiO{sub 4}-LiBSiO{sub 4}. Glasses were heat-treated following a schedule that traversed the crystallization temperatures of carnegieite (NaAlSiO{sub 4}), nepheline, and eucryptite (LiAlSiO{sub 4}) as determined by thermal analysis. Samples were analyzed using X-ray diffraction (XRD), Raman spectroscopy, and differential scanning calorimetry (DSC). It was observed that Li glasses tended to crystallize at higher boron levels than Na glasses. This behavior may result from the relationship between the structure of the glass network and the structure of the resulting crystal and the relative need for atomic rearrangement prior to crystallization in the Na bearing glass. (authors)

• Research Organization: WM Symposia, Inc., PO Box 27646, 85285-7646 Tempe, AZ (United States)
• OSTI ID: 22838160
• Report Number(s): INIS-US--19-WM-16323
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
ALUMINIUM SILICATES
CALORIMETRY
CONTAINERS
CRYSTALLIZATION
GLASS
HANFORD RESERVATION
HEAT TREATMENTS
HIGH-LEVEL RADIOACTIVE WASTES
LITHIUM COMPOUNDS
MELTING POINTS
RAMAN SPECTROSCOPY
SODIUM COMPOUNDS
THERMAL ANALYSIS
X-RAY DIFFRACTION