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Profile of Fire clay bricks

Date:2015-10-16 14:51 | From:Zhengzhou Sunrise Refractory | Author:admin

Fire clay bricks are sticky soil products which refer to Al2O3 containing 30%~40% aluminum silicate material. The main mineral composition of fire clay bricks are kaolinite(Al2O3•2SiO2•2H2O) and 6%~7% impurities(oxide of potassium, sodium, calcium, titanium and iron). Fire clay bricks adopt 50% soft clay and 50% hard clay clinker, ingredient by a certain size, and sinter under high temperature of 1300~1400℃ after forming and drying. The sintering process is mainly the process of decomposition of kaolinite which continuously dehydrates to mullite(3Al2O3•2SiO2). SiO2 and Al2O3 form eutectic low melting point of silicate with impurities in the process of sintering and surround the mullite crystal around.

fire clay bricks

Fire clay bricks are the weak acid refractory products which can resist acid melting slag and the erosion of acid gas, good thermal property and resist rapid heat and cold. The refractoriness of fire clay bricks is roughly the same with silica bricks which are up to 1690~1730℃, however, refractoriness under load of fire clay bricks is 200℃ lower than silica bricks. Duo to the low refractoriness under load, fire clay bricks will shrink at high temperature which lead to the lower thermal property and lower mechanical strength than silica brick, so fire clay bricks are only used in the secondary parts of coke oven, such as regenerator seal wall, small flue lining bricks and regenerator, door lining brick, roof and riser lining brick.

As the clay brick contains not only high refractoriness mullite crystal, but also amorphous glass phase with nearly half of the low melting point. Among the temperature of 0~1000℃, the volume of fire clay bricks expand with temperature increasing, and the linear expansion ratio is 0.6%~0.7%.  However, when the temperature reaches 1200℃, the volume will shrink from the maximum with the temperature increasing.

Zhengzhou Sunrise Refractory Co., Ltd. is mainly engaged in the research and development of refractory products. Sunrise can provide high quality fire clay bricks, the specific index is as below,

Item N-1 N-2a N-2b N-3a N-3b N-4 N-5
Refractoriness SK 31 30 30 29 29 28 27
1750 1730 1730 1710 1710 1690 1670
Chemical Al2O3 40 39 34 34 32 32 31
composition Fe2O3 2.1 2.1 2.3 2.3 2.5 2.5 2.5
Apparent 22 24 26 24 26 24 26
Bulk Density 2.15 2.1 2.1 2.05 2.05 2.05 2
Cold Crushing 30 25 20 20 15 20 15
Strength Mpa
0.2Mpa 1400 1350 1350 1320 1320 1300 1300
Under Load
T0.6 ℃ ≥
Reheating 1400℃  0.5 0.6 0.7        
Change 1350℃       0.7 0.7 0.7 0.7

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