Clay brick is also called fireclay brick or chamotte brick. Clay brick is the most widely used refractory products with the largest output. The raw material of clay brick is fireclay chamotte, plastic chamotte or semi plastic chamotte is used as binder. The quality of fireclay bricks fluctuates greatly due to the chemical composition of raw material is not stable, and the production crafts are different.
The chemical and mineral composition of clay brick. Clay bricks usually contain 30%~48% of Al2O3, 50%~65% of SiO2, and a little amount of alkali metals, alkaline earth metal oxides(TiO2, Fe2O3, etc). The mineral compositions of fireclay bricks are: mullite, cristobalite, quartz and glass phase.
The refractoriness of clay bricks is usually between 1580~1750℃, the higher Al2O3/SiO2 ratio, the higher the refractoriness. When there are more low melting point impurities, the refractoriness of the products significantly decreases.
The refractoriness under load temperature of fireclay brick is about 1250~1450℃, the variation range is very large. Deformation beginning temperature is relatively low, temperature difference between 40% deformation is about 200~250℃.
Clay brick has very low thermal expansion rate, 20~1000℃ average linear expansion rate is 4.5~6*10-6 /℃. Chamotte brick also has relatively low thermal conductivity.
Clay brick has good thermal shock resistance, but the fluctuation scope is very large. 1100℃ water cooling recycling tests is usually higher than 10 times, that’s because clay bricks have low thermal expansion coefficient, there is no significant crystal transfer at high temperature, and have plasticity at high temperature.
Chemical corrosion resistance. clay brick is weak acid refractory, it has good acid slag corrosion resistance, but weak resistance to basic material corrosion.
Clay bricks has relatively good acid slag corrosion resistance, so they are suitable for the masonry of acidic kiln working lining. Since the chemical composition and mineral phases of clay bricks varies significantly, their high temperature performance differs greatly, so as their application.
Glass kiln large scale clay bricks are clay blocks used to mason glass kiln, unit weight is no less than 50 kg.
|Fe2O3 % ≤||1.5||1.8|
|RUL 0.2 Mpa ℃ ≥||1450||1400|
|Reheating linear change(1400℃, 2h)||0~-0.4||0~-0.4|
|Cold compression strength Mpa ≥||49||34.3|
Clay bricks used in blast furnace should have high cold crushing strength and endure the abrasion of material loading, have small volume shrinkage under long term high temperature working condition, low apparent porosity, low Fe2O3 content, etc.
|Fe2O3 % ≤||1.7||1.7|
|RUL 0.2 Mpa ℃ ≥||1450||1430|
|Reheating linear change(1450℃, 3h)||0~-2||0~-3|
|Cold compression strength Mpa ≥||58.8||49.0|
Hot blast furnace clay bricks should have good thermal shock resistance, high rupture under load temperature, low creep. Hot blast furnace clay bricks are mainly used in regenerator chamber, partition wall and so on.
|RUL 0.2 Mpa ℃ ≥||1400||1350||1300|
|Reheating linear change||(1450℃, 3h)0~-0.4||(1350℃, 3h)0~-0.3||(1350℃, 3h)0~-0.5|
|Cold compression strength Mpa ≥||29.4||24.5||19.6|