Sulfur solubility in low activity waste glass and its correlation to melter tolerance

• Published in: International journal of applied glass science Vol. 10; no. 4; pp. 558 - 568
• Main Authors: Skidmore, Chloe H., Vienna, John D., Jin, Tongan, Kim, Dongsang, Stanfill, Bryan A., Fox, Kevin M., Kruger, Albert A.
• Format: Journal Article
• Language: English
• Published: Westerville Wiley Subscription Services, Inc 01.10.2019
• Subjects: characterization; Chromium oxides; Composition; Crucibles; Glass; Glass & glassware industry; glass forming melts‐chemical analysis; glass forming systems‐volatilization; modeling; Partitioning; properties‐borosilicate; properties‐glass forming melts; Saturation; Solubility; Sulfur; Sulfur trioxide; Vaporization
• DOI: 10.1111/ijag.13272
• ISSN: 2041-1286

Hanford low‐activity waste (LAW) glasses with high sulfur concentrations are subject to salt segregation in the melter, which hinders melter operation by corroding components and shortening the melter life. To better predict the point at which salt accumulates on the melt surface, the development of sulfate solubility models is needed. Using a sulfur saturation method, crucible scale melts for 13 LAW glasses with varying sulfur solubilities were conducted. The resulting salt and glass compositions were reported and the change in component partitioning following the saturation process was examined to better understand potential changes in overall glass composition. It was shown that both Cr2O3 and Cl experience significant losses, with ~28% of Cr2O3 partitioning into the salt phase and Cl primarily volatilizing out of the melt (~23% partitioned to salt and ~40% lost as off gas). These patterns can be accounted for during model development. Measured sulfur solubilities were also compared to previously reported data. It was found that crucible sulfur solubility ranged from 0.95 to 2.14 wt% SO3 with a high correlation ([Rfit2=0.94]) between crucible solubility and melter tolerance. These results suggest that crucible scale sulfate solubility data can be used to predict SO3 tolerance in the melter feed.