Performance Requirements of Refractories for Hot Blast Stove

The requirements of refractories for hot blast stove are followings:

1）Good heat storage performance. It requires high density and high specific heat capacity. Silica brick has a low density and bad heat storage capacity. It is used in the area less than 600℃and requires heat or cold slowly to keep quartz crystals transform slowly without damaging material.
2) High thermal conductivity. High thermal conductivity makes the regenerator can endothermic and exothermic efficiently in the cycle of heat exchanger. Thermal conductivity is one of the most important performances of refractories and it is related to chemical composition、mineralogical phase components 、density、microstructure and temperature of materials.  The thermal conductivity will be higher with the increase of Al2O3 content in aluminum-silicon refractories. So high alumina bricks are usually used as checker brick for hot blast stove to raise  blast temperature because of high thermal storage capacity.
3)Low coefficient of linear expansion.The linear expansion coefficient refers to the properties of the refractory which increase in volume and length with the increase in temperature. Before 600℃, the linear expansion rate of silicon brick is very large; The linear expansion rate will not change after beyond 600℃. Therefore, the use temperature of silicon brick should not be lower than 600℃.