The new generation of mullite refractories are proving to be a major success in glass furnace regenerator superstructures, sweeping away the previously dominant position of basic refractories in these applications. The regenerator principle for heat recovery pioneered by the Siemens brothers is now 150 years old, however, increased demands placed on the regenerative system have been met by improved and innovative refractories which make this system as relevant today as when first conceived. Attributes of low thermal conductivity, low thermal expansion in conjunction with chemical stability and thermal shock resistance place mullite in the premier rank when deliberating regenerator construction. Mullite regenerator superstructures have been widely used in the glass container industry with campaigns now reaching 16+ years. The opportunities created by mullite superstructure are highlighted in this paper; specifically why mullite zoning is key to the superstructure campaign; their ability to withstand alkali in thermo-mechanical situations and finally the potential heat saving and efficiencies that can be obtained compared with basic superstructure. In addition, the adoption of mullite regenerators for the float glass industry is discussed. Case studies are described showing mullite regenerators at campaign completion.
