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The process flow of refractory brick manufacturers to produce silica bricks

The process flow of refractory brick manufacturers to produce silica bricks

The raw materials of silica bricks are silica, waste bricks, lime, mineralizers and organic binders. The addition of waste silica bricks not only reduces the combustion expansion of the bricks, but also reduces the fire resistance and strength of the products. Therefore, Henan refractory brick manufacturers are determined according to different situations. The principle is that the larger the unit weight of the product, the more complex the shape and the more added. Generally controlled within 20%.

Lime is added to inferior materials in the form of milk of lime. The milk of lime acts as a binder, increases the strength after drying, and acts as a mineralizer during the combustion process. The quality requires 90% active Cao, no more than 5% carbonate, and a block size of about 50mm. The mineralizer used in production is mainly rolled steel scale. The quality requirement is that the iron oxide content is greater than 90%, which must be pulverized with a ball mill, and the part with a particle size of less than 0.088mm should account for more than 80%.

The common organic binder is sulfite slurry waste liquid.

There are four general principles for determining the composition of silica brick particles;

1) When selecting the critical particle size, the stability of the maximum density and high temperature combustion volume should be ensured;

2) It is expected that the critical particles in the bad materials are smaller and the fine particles are more;

3) When using a mixture of different types of silica, add coarse particles at high temperature and fine particles at low temperature;

4) For silica raw materials with dense texture, the particles can be coarser, otherwise finer.

Production practice shows that the critical particle size of ordinary silica brick is 2~3mm, and when vein quartz is used as raw material, the maximum particle size is about 2mm.

The molding characteristics of silica bricks are mainly reflected in three aspects: the molding characteristics of the blank, the complex shape of the brick shape and the large difference in single quality.

Silicon billet is a low plastic material, so the molding pressure should be increased appropriately. Coke oven silica bricks have complex shapes, single weight, and some have a thickness of 160mm, so it is best to use double-sided molding. If the vibration modeling method is adopted, its advantages are more obvious. Silica bricks will expand in volume when they are fired, so the size of the brick mold should be reduced accordingly.

Silicon brick will undergo phase change during the firing process, which brings difficulties to firing. Therefore, the physical and chemical changes of the kiln body, the shape and size of the defective body, and the characteristics of the kiln body should be considered comprehensively

1) When the temperature is lower than 600℃, the temperature should be raised quickly and evenly;

2) 700~1100℃ heating rate is faster than the former;

3) In the temperature range of 1100~1430℃, the heating rate should be gradually reduced;

4) Weak reduction flame combustion is used in the high temperature stage, and the temperature in the kiln is evenly distributed to avoid damage to the brick body by the flame. After reaching the maximum sintering temperature, there should be enough holding time, and the holding time fluctuates between 20~48h;

5) It can be cooled quickly above 600~800℃, and it is better to cool slowly at low temperature.