Tank 38H Desilication Study
In support of potential option for treating high level waste supernates that have elevated levels of silicon, a series of tests was performed to measure the rate of desilication of High Level Waste simulants as a function of time at an elevated temperature (50 degrees Celsius). These studies indicate that the addition of aluminate ion to typical wastes like Tank 38H supernate can reduce the soluble silicon concentration. Previous work in highly supersaturated simulants indicated reaction times would be on the order of days to weeks. In this study, we examined simulants that were only mildly supersaturated with respect to aluminosilicate formation. Because the silicon concentration was limiting, the desilication data fit to pseudo first order reaction kinetic expressions. It was determined that the reaction rate constant was affected by the degree of supersaturation. This indicated that the reaction times to complete desilication of a high level waste supernate may be much longer than expected and may approach month-long time frames at 50 degrees Celsius. Additionally, the data were examined in terms of crystal growth kinetics used by Addai-Mensah and other researchers in the aluminum industry. The order of crystal growth observed in these tests with a Tank 38H simulant was 1 and was similar to that measured for industrial simulants.
- Research Organization:
- Savannah River Site (SRS), Aiken, SC (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC09-96SR18500
- OSTI ID:
- 799320
- Report Number(s):
- WSRC-TR-2001-00582; TRN: US0300017
- Resource Relation:
- Other Information: PBD: 13 Feb 2002
- Country of Publication:
- United States
- Language:
- English
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