The crystallization behavior of the West Valley reference borosilicate glass. Progress report, October 1, 1986--September 30, 1987 [electronic resource].

Published: Washington, D.C. : United States. Dept. of Energy, 1988.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Physical Description: 128 pages : digital, PDF file
Additional Creators: United States. Department of Energy and United States. Department of Energy. Office of Scientific and Technical Information

Access Online

www.osti.gov

Availability

Finding items...

Restrictions on Access

Free-to-read Unrestricted online access

Summary

The crystallization behavior of a fully simulated reference borosilicate glass was studied. This work was required by the Waste Acceptance Preliminary Specifications. It included preparing and characterizing the base glass in various redox states, and assessing the influence of redox state on crystallization behavior. Characterization tools included optical and electron microscopy, wet chemical analysis, x-ray diffraction, dilatometry, and differential scanning calorimetry. Effect of cooling a melt at a rate and history simulating in-canister cooling used for full-scale vitrification at West Valley also was determined. The fully oxidized glass composition study contains residual crystalline phases (spinel and cerium-thorium oxide) at 0.4--1.6 vol %. Upon isothermal heat treatment above a measured glass transition temperature of 478C, but below the estimated liquidus of 1000C, crystallization would increase to 4--5 vol % for times up to 384 hours. Crystallization products included spine, acmite, cerium-thorium oxide, and alumino silicates. Crystallization rate was maximum at 700--800C. After 12 hours at 800C the glass crystallized to 3.0 vol %. This same glass, when reduced to a redox state where the ratio of Fe{sup ++}/total iron was 10%, showed a lower crystallization maximum, i.e., 600--700C. The glass transition temperature of this partially reduced glass also was lowered from 478C (fully oxidized) to 474C. All of these observations are in accord with the general theories of glass science. A critical cooling rate of 1.48C/min would be sufficient to limit crystallization to less than 2.0 vol %. This predicted value was confirmed by cooling a melt at this temperature and then estimating the volume percent crystallization.

Report Numbers

E 1.99:doe/ne/44139--44
doe/ne/44139--44

Subject(s)

Other Subject(s)

Note

Published through SciTech Connect.
04/01/1988.
"doe/ne/44139--44"
"DE95004250"
""
Sehgal, J.; Mathur, A.; Pye, L.D.; McPherson, D.; Joseph, I.; Butts, D.; Capozzi, C.
West Valley Nuclear Services Co., Inc., West Valley, NY (United States)

Type of Report and Period Covered Note

Annual; 01/01/1986 - 12/31/1987

Funding Information

AC07-81NE44139

View MARC record | catkey: 14417184