Single-pass flow-through experiments were conducted with aluminoborosilicate waste glasses to evaluate how changes in solution composition affect the dissolution rate (r) at 40°C and pH(23°C) = 9.0. The three prototypic low-activity waste (LAW) glasses; LAWE-1A, -95A, and -290A, used in these experiments span a wide range covering the expected processing composition of candidate immobilized low-activity waste (ILAW) glasses. Results suggest incongruent release of Al, B, Na, and Si at low flow-rate (q) to sample surface area (S) [log10 (q/S) -7.9 (m/s)]. Forward dissolution rates, based on boron release, are the same irrespective of glass composition, evident by the dissolution rates being within the experimental error of one another [r1A = 0.0301 ±0.0153 g/(m2 d), r95A = 0.0248 ±0.0125 g/(m2 d), and r290A = 0.0389 ±0.0197 g/(m2 d)]. Finally these results support the use of a chemical affinity based rate law to describe glass dissolution as a function of solution composition.
Revised: July 11, 2007 |
Published: March 1, 2007
Citation
Richards E.L., A.M. Davis, and E.M. Pierce. 2007.Evaluation of Solution Composition Aluminoborosilicate Waste Glass Dissolution at 40°C. In Preprints of extended abstracts presented at the ACS National Meeting, American Chemical Society, Division of Environmental Chemistry, 2007, 47, 125-134. Washington, District Of Columbia:American Chemical Society, Division of Environmental Chemistry.PNNL-SA-52923.