The main raw materials of high siliceous clay bricks are barren clay (calcined hard clay, kaolin or pyrophyllite) and natural quartz sand. The content of SiO2 in the prepared material is more than 65%, and the content of Al2O3+TiO2 is more than 30%. According to different types of raw materials, high-silica clay bricks can be divided into two types: quartz-kaolinite high-silica clay bricks and quartz-clay high-silica clay bricks. The former has a maximum content of 75~80% SiO2, a refractoriness greater than 1710°C, and an apparent porosity greater than 25%. The refractoriness of refractory bricks is low, between 1610-1700 ℃, due to the influence of chemical composition. When producing high siliceous clay bricks, it is even more important to choose the appropriate critical particle size. If the particles of quartz sand are too fine, there will be more opportunities to combine with the clay. Crystal transformation, resulting in volume expansion of brick, loose structure, mechanical strength and high temperature performance decline. In order to achieve the ideal high-silica clay brick production process, the following issues should be paid attention to:
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1) It is necessary to choose the binding clay with strong bonding and plasticity, and low sintering temperature, so that it can fully combine with the barren particles and prevent the volume change of quartz due to crystal transformation at high temperature;
2) Use natural quartz sand with high hardness and dense structure, and add as little amorphous cementitious material as possible, because natural quartz sand plays a skeleton role in the brick body, within the possible range, more quartz sand should be added, at least 40% above;
3) The sintering temperature is the key to obtaining dense products and should be controlled between 1380-1410 °C. The main physical properties of high siliceous clay bricks depend on the SiO2 content in the bricks, followed by the critical particle size of quartz sand. If more than 98 brims of fine powder can pass through the 10,000-hole/cm2 screen in the ingredients, it is sure to produce high-density and high-silica clay bricks with a bulk density greater than 2.2g/cm3.
High siliceous clay bricks are stable in volume at a certain temperature. Long-term use does not cause excessive volume expansion or contraction, and the softening temperature under load is also higher than that of ordinary clay bricks, so it is very suitable for regenerators or steel ladles. lining. From the perspective of raw material resources, the foamed sandstone in Southwest my country and the pyrophyllite in the coastal areas of East China can be slaughtered as raw materials for the production of high-silica clay bricks.
The production of high-density high-silica clay bricks can also be formulated with natural silica and soft clay. Silica should be fine silica powder with strong dispersibility, and more than 98% of the new powder should pass through the sieve of 0.060mm (ie 10000 mesh/cm 2 ). High-density and high-silica sticky bricks are suitable for building the regenerator of large coke ovens, and can also be used as the lining of steel ladles.
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Zhengzhou Shennan Refractory Co.,Ltd are professional in producing high silica clay bricks , any demands, please don't hesitate contact with me.
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+86-15238007351 |
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+86-371-86039318 |
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annie@snrefractory.com |
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www.snrefractory.com |
