It is also necessary to add the right amount of flammable substances or use gas generation to create a porous structure.

The firing method of lightweight silica bricks mainly includes the following steps:

Raw material preparation: The preparation of lightweight silica bricks usually uses finely crushed silica as the main raw material, and its critical particle size is usually not greater than 1 mm, of which no less than 90% of the particles are less than 0.5 mm. In addition, it is necessary to add an appropriate amount of flammable substances or use the gas generation method to form a porous structure.

Forming: After mixing the prepared raw materials evenly, they can be formed by vibration molding or mashing. After forming, the billet needs to be dried at 110 °C for 4~24 hours to ensure the stability and strength of the billet.

Firing Process: The firing process is carried out in several stages. First, preheating and constant temperature treatment are carried out at lower temperatures, and gradually heating up to the high temperature stage. Specific steps include:

The heating period of 20 ~ 200 °C is 5 days, the heating rate is 1.5 °C/h, and the constant temperature of 200 °C is 5 days.

The heating period of 200 ~ 300 °C is 4 days, the heating rate is 1.0 °C/h, and the constant temperature of 300 °C is 5 days.

The heating period of 300 ~ 600 °C is 10 days, the heating rate is 1.25 °C/h, and the constant temperature of 600 °C is 6 days.

The heating period of 600 ~ 800 °C is 4 days, the heating rate is 2 °C/h, and the constant temperature of 800 °C is 2 days.

The heating period of 800 ~ 1000 °C is 1 day, and then the blast furnace gas is normalized, so that the hot blast furnace as a whole is further baked, and the temperature continues to rise evenly to reach the air temperature level required by the blast furnace.

Characteristics and applications of lightweight silica bricks: Lightweight silica bricks have the characteristics of uniform microstructure, low bulk density, excellent thermal insulation performance, high loading and softening temperature, and good high temperature volume stability. It is mainly used to require thermal insulation or reduce its own weight without direct contact with the molten material, not affected by corrosive gases, and not subject to rapid changes in temperature of the kiln parts.