Modeling of Boehmite Leaching from Actual Hanford High-Level Waste Samples
The Department of Energy plans to vitrify approximately 60,000 metric tons of high level waste sludge from underground storage tanks at the Hanford Nuclear Reservation. To reduce the volume of high level waste requiring treatment, a goal has been set to remove about 90 percent of the aluminum, which comprises nearly 70 percent of the sludge. Aluminum in the form of gibbsite and sodium aluminate can be easily dissolved by washing the waste stream with caustic, but boehmite, which comprises nearly half of the total aluminum, is more resistant to caustic dissolution and requires higher treatment temperatures and hydroxide concentrations. In this work, the dissolution kinetics of aluminum species during caustic leaching of actual Hanford high level waste samples is examined. The experimental results are used to develop a shrinking core model that provides a basis for prediction of dissolution dynamics from known process temperature and hydroxide concentration. This model is further developed to include the effects of particle size polydispersity, which is found to strongly influence the rate of dissolution.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 910261
- Report Number(s):
- PNNL-SA-51903
- Journal Information:
- Separation Science and Technology, 42(8):1719-1730, Journal Name: Separation Science and Technology, 42(8):1719-1730 Journal Issue: 8 Vol. 42; ISSN 0149-6395; ISSN SSTEDS
- Country of Publication:
- United States
- Language:
- English
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Boehmite Actual Waste Dissolutions Studies
DEVELOPMENT OF A KINETIC MODEL OF BOEHMITE DISSOLUTION IN CAUSTIC SOLUTIONS APPLIED TO OPTIMIZE HANFORD WASTE PROCESSING
Related Subjects
ALUMINIUM HYDROXIDES
ALUMINIUM OXIDES
Boehmite
Dissolution
High Level Waste
CHEMICAL REACTION KINETICS
DISSOLUTION
HANFORD RESERVATION
HIGH-LEVEL RADIOACTIVE WASTES
LEACHING
MATHEMATICAL MODELS
RADIOACTIVE WASTE PROCESSING
SLUDGES