What is Zero-expansion silica bricks？
Zero-expansion silica bricks are also called fused silica bricks or thermal shock-resistant silica bricks. It has anti-acid slag corrosion performance. Higher high temperature strength. The temperature of softening under load is 1620～1670℃. Long-term use at high temperature without deformation. Good thermal shock stability (heat exchange in water is 1~30 times). Natural silica is used as raw material, and an appropriate amount of mineralizer is added to promote the conversion of quartz in the green body into tridymite. Slow firing at 1350-14 30°C under reducing atmosphere.
In the process of firing silica bricks, why should they be fired slowly? The main purpose is to convert quartz into tridymite. The more tridymite, the smaller the true specific gravity and the higher the melting point. Because phosphorus quartz is a spearhead twin crystal, and the spearhead twin crystal will form an interlaced network structure, giving the product a higher Load softening temperature and mechanical strength. Therefore, it is generally hoped that there is as much tridymite as possible in the fired silica brick, followed by cristobalite, and the less residual quartz, the better.
Advantages of Zero-expansion silica bricks
1. SiO2 content greater than 99%, excellent corrosion resistance and acid resistance;
2. Low Fe2O3 content is less than 0.1%, no pollution to products (such as molten glass, etc.);
3. Low flux index (Al2O3+2R2O) is less than 0.3%;
4. The thermal expansion rate is close to zero, so there is no need to reserve expansion joints when repairing, so as to increase the tightness of the masonry;
5. Excellent thermal stability, the product will not burst during hot repair, and repair work can be carried out directly under the condition of high temperature without stopping the furnace;
6. After repair (hot repair), no peeling will occur, and it is safe and reliable for long-term use;
7. Good corrosion resistance, due to the lack of calcium, corrosion cannot form;
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