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Title: Modeling of Boehmite Leaching from Actual Hanford High-Level Waste Samples

Conference ·
OSTI ID:21294733
; ; ;  [1]
  1. Pacific Northwest National Laboratory, Richland, WA (United States)

The U.S. Department of Energy plans to vitrify approximately 60,000 metric tons of high-level waste (HLW) sludge from underground storage tanks at the Hanford Site in Southwest Washington State. To reduce the volume of HLW requiring treatment, a goal has been set to remove a significant quantity of the aluminum, which comprises nearly 70 percent of the sludge. Aluminum is found in the form of gibbsite and sodium aluminate, which can be easily dissolved by washing the waste stream with caustic, and boehmite, which comprises nearly half of the total aluminum, but is more resistant to caustic dissolution and requires higher treatment temperatures and hydroxide concentrations. Chromium, which makes up a much smaller amount ({approx}3%) of the sludge, must also be removed because there is a low tolerance for chromium in the HLW immobilization process. In this work, the coupled dissolution kinetics of aluminum and chromium species during caustic leaching of actual Hanford HLW samples is examined. The experimental results are used to develop a model that provides a basis for predicting dissolution dynamics from known process temperature and hydroxide concentration. (authors)

Research Organization:
WM Symposia, 1628 E. Southern Avenue, Suite 9 - 332, Tempe, AZ 85282 (United States)
OSTI ID:
21294733
Report Number(s):
INIS-US-09-WM-07388; TRN: US10V0264040923
Resource Relation:
Conference: WM'07: 2007 Waste Management Symposium - Global Accomplishments in Environmental and Radioactive Waste Management: Education and Opportunity for the Next Generation of Waste Management Professionals, Tucson, AZ (United States), 25 Feb - 1 Mar 2007; Other Information: Country of input: France; 9 refs
Country of Publication:
United States
Language:
English