Silica brick is a refractory product

Silica brick is a refractory product with silica as the main component, and its content is above 93%. It is made of quartzite as raw material, adding a small amount of mineralizing agent and fired by high temperature. It is an acidic refractory material with strong resistance to acidic slag erosion, but strong erosion ability by alkaline slag. It is easily destroyed by oxides containing Al2O3, K2O, Na2O, etc., but has good resistance to oxides such as CaO, FeO, Fe2O3, etc.

The mineral composition of silica brick is a multiphase structure with the coexistence of scale quartz, square quartz, a small amount of residual quartz and glass.

The higher load deflection temperature is an excellent characteristic of silica brick. Its melting point is close to that of quartz and square quartz (1670℃, 1713℃) and fluctuates between 1640℃ and 1680℃. After recalcination of the silica brick, irreversible volume expansion will occur due to the continuous transformation of the quartz remaining in the brick. In the interval from 300°C to near the melting point, the volume of silica bricks is stable, and the total volume expansion is about 1.5% to 2.2% when heated to 1450°C. However, this expansion will make the joints tight and ensure that the masonry has good airtightness and structural strength.

At the same time, the biggest disadvantage of silica brick is low thermal shock stability, followed by low refractoriness (generally 1690℃~1730℃), which limits its application scope.

Silica bricks are mainly used in coke ovens, glass melting furnaces, acid steelmaking furnaces and other thermal equipment.

Silicon bricks for glass kilns

Silica bricks for glass kilns are used to construct high temperature components for glass tank kilns. They have the following characteristics.

✳ Small bulk density

✳ Chemical resistance

✳ Non-polluting to glass

✳ Volume stability at high temperatures, furnace body does not change due to temperature fluctuations

Silica bricks for coke ovens

Modern coke ovens are large thermal equipment built by tens of thousands of tons and nearly a thousand types of brick refractories, of which silicon bricks account for 60% to 70% of the usage. Silica bricks for coke ovens mainly consist of scaled quartz and are mainly used for building heat storage chamber walls, chutes, combustion chambers, charring chambers and coke oven roofs. Silica bricks for coke ovens mainly have the characteristics of high load softening temperature, high thermal conductivity, good thermal shock resistance and good volume stability at high temperature.

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