Zero Expansion Silica Brick

Zero expansion silica bricks are also called fused quartz bricks or thermal shock resistant silica bricks

Characteristics

Extremely low thermal expansion coefficient, excellent resistance to rapid cooling and heating, good high temperature structural strength, high Si0, content, no cracking and peeling during use, close to zero low thermal expansion performance, after repair, long-term use is safe and reliable.

This product can be widely used in various coke ovens and glass kilns for rapid thermal repair projects. Our company not only provides coke oven hot repair methods, but also undertakes coke oven hot repair projects.

 

Zero expansion silica bricks are made of fused quartz as raw material and are used to produce a kind of thermal shock resistant zero expansion silica brick refractory products. Zero expansion high purity silica bricks used for rapid repair are new materials for zero expansion silica bricks for glass kilns, coke ovens, hot repairs, and continuous casting intermediate tank bottoms and crystallizers. This brick has excellent thermal shock resistance.

The raw materials are natural crystal, vein quartz or quartz sand, which are melted at high temperature to obtain fused quartz.

Since the linear expansion coefficient of quartz glass is small, it is only 5×10-7K-1 at 20℃ and only 11x10-7K-1 at 1200℃, which is only 1/10 of ordinary glass, so it has good thermal shock resistance. The quartz crystal in quartz glass can slowly transform into α-cristobalite crystal above 1000℃, and α-cristobalite will transform into β-cristobalite at low temperature and change volume, causing cracking, looseness and reduced thermal shock resistance of the product. Quartz glass not only has many valuable properties, but also has a promising material for metallurgy and chemical industry due to its low thermal conductivity.

The production process of zero expansion silica bricks involves wet grinding quartz glass into slurry in a ball mill and casting it into shape in a gypsum mold. The density of the brick body is 1.75~1.80g/cm3, and the brick body is dried and fired at a temperature of 1100 ℃.

In order to improve the strength of the product and reduce the porosity, the fired product can be immersed in an inorganic or organic solution. The nozzle is divided into large, extra-long products and general products according to the shape. The production of the nozzle can be made of waste and scraps of fused quartz glass products and ground into fine powder, so the cost is low.

Cold repair of kilns is difficult, time-consuming and costly, so many kilns are forced to stop using after being damaged. In order to meet the development needs of hot repair of kilns, our company has developed zero-expansion silica bricks with good performance, which solves the problem of poor thermal stability of ordinary silica bricks and can meet the requirements of rapid heating. It does not require long-term furnace baking and can be used after the furnace is built.

1) Low thermal expansion rate and stable volume at high temperature.

2) The product has no dimensional change, no cracking, no deformation, and can be directly repaired at high temperature without stopping the furnace.

3) After the glass kiln is repaired, there is no impurity pollution, no erosion and peeling, and it is safe and reliable.

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