Configuration of Refractory Materials for the Bottom of Glass Melting Furnace

The configuration of refractory materials for the bottom of glass melting furnaces is crucial for withstanding the harsh conditions present in this area. Typically, the bottom of a glass melting furnace is only subject to erosion from the liquid phase and does not experience erosion from the glass liquid surface or the three-phase interface. However, erosion upwards can occur when the glass liquid reaches beneath the stratified refractory bricks. Erosion products on the furnace bottom tend to be retained on the surface of the refractory material due to gravity, to some extent, allowing for the use of refractory materials with poorer erosion resistance in this area. However, changes in the convection pattern of the liquid flow or variations in furnace load may lead to defects in the glass when using refractory materials with lower erosion resistance in this area.

Bubble formation from the bottom of the furnace is a common practice. Local turbulence generated by bubble action requires the use of refractory materials with better erosion resistance in this area. Typically, this involves the separate placement of thicker fused cast refractory materials from the customary brick paving of the furnace bottom. These thicker bricks, by preventing disturbance damage caused by stratified structures, contribute to a more balanced and consistent furnace lifespan.

The presence of metallic impurities in glass batch materials has a significant impact on the furnace bottom structure. The furnace bottom is the area where metallic deposition into the furnace is most likely to occur. Metal deposited on the furnace bottom structure can corrode pores in the refractory material, similar to the upward erosion caused by glass liquid on refractory materials. Generally, metals with lower melting points exhibit higher and more significant rates of erosion compared to iron and its alloys. In some cases, metals can be directly reduced from the glass due to conditions within the furnace.

For glass melting furnaces producing high-alumina content glass, the furnace bottom structure is unique compared to general furnace bottom configurations in the glass industry, as there is a tendency for the bottom layer or overlying refractory materials to drift or float due to the high density of glass. Therefore, the optimal furnace bottom structure for melting high-lead glass is a single-layer furnace bottom made of a single refractory material. The most commonly used material for this purpose is fused cast zirconium-aluminum-silicate refractory material.