Application Of Silica Bricks In Hot Blast Stove

Silica brick is a type of acid refractory. Due to its advantages such as good volume stability and good creep resistance, it is used in the high-temperature parts of hot blast stove. 

The air temperature of hot stoves had been increased from 500-650℃ in 1940s to 1000℃ in 1970s. In 1980s, the air temperature of large hot stoves had been increased to 1350℃. Due to the increase of the air temperature, fire clay bricks are gradually replaced by silica bricks and high alumina bricks in the high-temperature parts of hot blast stoves. 

 

Silica brick used in hot blast stove mainly consists of tridymite. It has the following features: 

1)Good volume stability and creep resistance at high temperature under load - it can be continuously used for one or two campaigns.

2)Good thermal shock resistance above 600℃ - it can be well adapted to the variability of the temperature and maintain the integrity of bricks and masonry. 

3)Better corrosion resistance than fire clay brick and common high alumina brick - the alkali substances in the coal gas and smoke can form a layer of glass phase on the surface of silica brick and prevent further corrosion. 

4)Higher thermal conductivity than fire clay brick and high alumina brick - this is conducive to store and release heat in a shorter time.

 

The products should have neat appearance and accurate size. The aperture error of checker bricks should be limited to ±1mm. Errors of bricks used in other parts should not exceed ±1％. In the external combustion stove, if the joints of pipes of the upper part adopts a combination of bricks, the bricks should be pre-assembled before installation. The cracks on the surface should not exceed 0.5mm. 

 

Silica bricks should be stored in a waterproof warehouse. If wet by water, dry under 100℃.  Expansion joints should be reserved according to the the thermal expansion coefficient. The temperature-time temperature curve for preheating should be made reasonably.