Aluminisilicate deposit buildup experienced during the tank waste volume-reduction process at the Savannah River Site (SRS) required an evaporator to be shut down. Studies were conducted at 80 ?C to identify the insoluble aluminosilicate phase(s) and to determine the kinetics of their formation and transformation. These tests were carried out under conditions more similar to those that occur in HLW tanks and evaporators. Comparison of our results with those reported from the site show very similar trends. Initially, an amorphous phase precipitates followed by a zeolite phase that transforms to sodalite and which finally converts to cancrinite. Our results also show the expected trend of an increased rate of transformation into denser aluminosilicate phases (sodalite and cancrinite) with time and increasing hydroxide concentrations.
Revised: September 26, 2007 |
Published: November 30, 2006
Citation
Mattigod S.V., D.T. Hobbs, K.E. Parker, D.E. McCready, and L.Q. Wang. 2006.Effects of Sodium Hydroxide and Sodium Aluminate on the Precipitation of Aluminum Containing Species in Tank Wastes. In Nuclear Waste Management: Accomplishments of the Environmental Management Science Program, ACS Symposium Series, edited by Paul W. Wang, Tiffany Zachry. 319 - 335. Washington Dc:American Chemical Society.PNNL-SA-51250.