In situ characterization of foam morphology during melting of simulated waste glass using x-ray computed tomography

Abstract During batch-to-glass conversion, a glass-forming melt connects, creating a foam layer between the batch and the glass melt. Due to its transience and opacity, investigation of this foam layer presents a formidable challenge. In this work, we use in situ x-ray computed tomography to characterize the foam morphology that evolves during batch-to-glass conversion of a simulated nuclear waste glass. Rapid 1-min scans with 38 μm voxels were performed to capture the foam structure during heating. Geometric volume, total porosity, and bubble size distribution are reported. Using evolved gas analysis and combining the temperature-dependent melt viscosity with x-ray data, we describe the evolution of foam structure during the foam growth and subsequent collapse.