Effects of Al2O3, B2O3, Li2O, Na2O, and SiO2 on Nepheline Crystallization in Hanford High Level Waste Glasses

Conference · Thu Sep 15 04:00:00 EDT 2016

DOI:https://doi.org/10.1002/9781119323624.ch15· OSTI ID:1344666

Kroll, Jared O.; Vienna, John D.; Schweiger, Michael J.

Nepheline (nominally NaAlSiO4) formation during slow cooling of high-alumina (25.4 - 34.5 mass% Al2O3) Hanford high level waste glasses may significantly reduce product durability. To investigate the effects of composition on nepheline crystallization, 29 compositions were formulated by adjusting Al2O3, B2O3, Li2O, Na2O, and SiO2 around a baseline glass that precipitated 12 mass% nepheline. Thirteen of these compositions were generated by adjusting one-component-at-a-time, while two or three components were adjusted to produce the other 16 (with all remaining components staying in the same relative proportions). Quantitative X-ray diffraction was used to determine nepheline concentration in each sample. Twenty two glasses precipitated nepheline, two of which also precipitated eucryptite (nominally LiAlSiO4), and one glass formed only eucryptite upon slow cooling. Increasing Na2O and Li2O had the strongest effect in promoting nepheline formation. Increasing B2O3 inhibited nepheline formation. SiO2 and Al2O3 showed non-linear behavior related to nepheline formation. The composition effects on nepheline formation in these glasses are reported.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1344666
• Report Number(s): PNNL-SA-114219; 830403000
• Country of Publication: United States
• Language: English