The application and features of refractory fire brick

Posted by annesheldon on August 29th, 2017

Clay refractory brick is Al2O3 content of 30% to 40% of aluminum silicate material of clay products. Clay brick is 50% soft clay and 50% hard clay clinker, according to a certain size requirements for ingredients, after molding, drying, in the 1300 ~ 1400 ℃ high temperature firing. The mineral composition of clay brick is mainly kaolinite (Al2O3 · 2SiO2 · 2H2O) and 6% ~ 7% impurities (potassium, sodium, calcium, titanium, iron oxide). stick
The calcination process of tiles is mainly due to the process of crystallization of kaolinite (3Al2O3 · 2SiO2). The SiO2 and Al2O3 in the clay brick form an eutectic and low melting point silicate with the impurity surrounding the mullite crystals during the firing process.

Clay refractory bricks are weak acid refractory products, can resist acid slag and acid gas erosion, resistance to alkaline substances slightly worse. Clay brick thermal performance is good, resistance to rapid cooling hot.

Clay refractory firebrick degree and silica brick comparable, up to 1690 ~ 1730 ℃, but the load softening temperature is lower than the silica brick 200 ℃. Because the clay brick contains high refractory mullite crystals, but also contains nearly half of the low melting point amorphous glass phase.

In the temperature range of 0 ~ 1000 ℃, the volume of clay brick with the temperature rise and uniform expansion, linear expansion curve is similar to a straight line, linear expansion rate of 0.6% to 0.7%, only half of the silicon brick. When the temperature reaches 1200 ℃ and then continue to heat up, the volume will start to shrink from the maximum expansion. The residual shrinkage of the clay brick leads to the cracking of the masonry gray seam, which is a major drawback of the clay brick. When the temperature exceeds 1200 ℃, the clay in the low melting point material gradually melted, because the particles by the surface tension and rely on each other very tight, resulting in volume shrinkage.

As the clay refractory fire brick load softening temperature is low, at high temperature shrinkage, thermal conductivity than silica brick 15% to 20%, mechanical strength is also worse than the silicon brick, so clay can only be used for the secondary parts of the coke oven , Such as regenerative room wall, small flue lining brick and regenerator lattice brick, door lining brick, roof and riser lining brick.

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Article Source: Generality High Alumina Brick and Clay Brick
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd 
Email: sales1@chinafirebrick.com
Website:http://www.chinafirebrick.com/