Brief introduction of the application of silica refractory brick in coke oven

Silica refractory brick contains more than 293% of SiO, and is made by crushing and burning of high-content silica. In order to bond and mold, 23% lime is mixed into the mud.

 

Siliceous refractory bricks have good thermal properties and high resistance to erosion of salts in moisture and ash due to their high SiO2 content. The refractoriness of silicon refractory brick can reach 1700 ~ 1750 ℃, and the load softening point can reach above 1520 ℃. Silica refractory bricks have poor resistance to rapid cooling and heat, and severe temperature fluctuations can damage the silica refractory bricks. This is because the density of SiO2 also changes with the change of temperature, which causes rapid expansion and contraction.

SiO2 can exist in three crystal forms, namely quartz, cristobalite and scale quartz. There are several allotropes for each type. Allotropic crystals have different lattices and densities, and all have stability in a certain temperature range, beyond which the crystal form transition occurs. The volume change of cristobalite at 180-270 ° C is dramatic, followed by quartz, while the volume change of scale quartz is gentler. The density of scale quartz is small, so the silica refractory bricks of coke oven want the density to be as small as possible, in order to have a large scale quartz content.

 

Increasing the thermal conductivity of the silica refractory bricks is beneficial for strengthening the focusing furnace, and increasing the density of the silica refractory bricks can improve the thermal conductivity. The price of refractory bricks for coke ovens varies according to the content of SiO2 used.