Thermal Conductivity of Refractory Materials Used in the Glass Production Industry

Refractory materials are widely used throughout the glass production industry. High-temperature exposure to glass melt and its vapors causes significant microstructure change in the refractories. Thermal conductivity of the refractories is also expected to change after long-time exposure to high temperatures. Salvaged silica bricks from float-glass and TV-panel furnaces were provided by PPG Industries and Thomson Consumer Electronics. These bricks had been in service for 10 years and 6.5 years respectively. A fusion-cast alumina refractory was also tested in this study. Thermal conductivity of the refractories was measured by a Hot Disk system. The single-side method was used to obtain thermal conductivity data non-destructively. Thermal conductivity values of the silica bricks had increased after their service. Thermal conductivity as a function of location also revealed variations at the hot- and cold-faces of the bricks. Thermal conductivity variations at the different locations in the fusion-cast alumina were also observed.