With the development of glass melting technology, the bottom of the glass furnace usually adopts multi-layer structure which has better insulation performance and reduces heat loss greatly. 

Paving block usually adopts sintered AZS, fused cast AZS, alpha-beta fused cast alumina block and zircon brick. For sintered refractories, the pores are open and the corrosive substances are easy to diffuse into the core areas, which will accelerate the corrosion and cause glass defects.

 

A certain proportion of cullets, which contain metal contaminants, are added to the raw materials. The metal is deposited on the bottom and corrodes the paving block. 

 

The paving block is in direct contact with glass liquid. The flowing glass liquid erodes the refractories and accelerates the corrosion. Fused cast refractories have better corrosion resistance than sintered refractories. Alpha-beta fused cast alumina block has a low blistering and stoning potential and cause also no defects, thus it has even better performance than fused cast AZS. 

 

To prevent the glass liquid from exuding through the bottom blocks, a layer of ramming masses is laid between the insulation blocks and the paving blocks. There are two ramming masses commonly used in the bottom: AZS ramming masses and zircon ramming masses. AZS ramming mass is made of 5mm fused cast AZS grains and other materials. It has a low porosity and stable performance and can resist the corrosion by glass liquid and mental well. Since AZS ramming mass has a higher content of Al2O3, it has better corrosion resistance than zircon ramming mass. 

 

The insulation block is generally made up of fireclay bricks to reduce heat loss and improve the melting temperature. 

 

However, the multi-layer structure also improves the temperature, accelerates the corrosion and makes the bottom one of the weak points of the glass furnace. During the campaign, sometime the bottom needs hot repair. It can save money and avoid the shutdown of the furnace. 

 

One of the way is to empty the glass furnace and drill in the areas eroded seriously. After cleaning the glass, spray the gunning materials on the damaged areas. Another way is to convey the refractory aggregates to the damaged parts with air flow through the spray gun. This way can be used when the furnace is empty or not. 

 

Zhengzhou Sunrise is a refractory material supplier from China, offering high quality refractory materials for glass furnaces, including fused cast AZS block, fused cast alumina block, fused cast high zirconia block, mullite brick, zircon brick, alumina bubble brick, magnesia brick, sillimanite brick, corundum brick, low porosity fireclay brick, high alumina brick, all kinds of glass furnace ramming masses, etc..