The Application Of Silica Bricks In Glass Furnaces

There are different types of glass furnaces with different sizes and structures for the production of glass, which have different requirements for refractories. The refractories used for the glass industry, especially the float glass furnaces, include fused cast refractories, silica brick and magnesia brick. 

Silica brick is a traditional refractory for the glass furnaces. It refers to the refractory containing 93% SiO2. It is made of silica containing 96% SiO2 with addition of mineralizing agent and a binder by mixing, shaping, drying and firing. The higher the content of SiO2, the higher the refractiness. 

 

It is kind of acid brick. It has great resistance to acid slags, high softening temperature under load, lower density and lower price. It is widely used in the the carbonization chamber, combustion chamber and partition wall of the coke oven, the crown of the glass furnace, high temperature load-bearing parts of the hot stove, carbon roaster and other thermal equipment.

 

It is mainly used in the crown and flame space of the glass furnaces. Its quality is closely related to the normal operation and service life of the glass furnaces. 

 

There are three generations of silica bricks. The first generation is common silica brick. The second is high quality silica brick. Compared to the common silica brick, high quality silica brick has high purity, high softening temperature, high content of tridymite and cristobalite, low impurities, low true density and low residual silica. The third generation is developed based on the second generation. The content of CaO is reduced from 2%-3% to 1%. The content of alkali metal oxides is less than 0.5%, FeO less than 0.2% and the apparent porosity is reduced from 20%-22% to 16%-18%. 

 

Silica brick is cheap, but it has excellent resistance to alkali slags. It can meet the regular requirement of the crown of the glass furnaces, but in oxygen-fuel furnaces, its service life can be reduced from 5-10 years to 2-3 years and becomes the weakest point. 

 

With the application of the oxygen combustion technology, silica brick is subjected to much severer environment. High quality silica brick is developed and used in the areas where the corrosion is mild and in severe areas fused cast alumina block, fused cast AZS block and spinel brick.