Refractory bricks can help industrial kilns resist high temperature corrosion and improve kiln performance and benefits. They are an indispensable part of high-temperature industrial kilns and an important line of defense for kilns.
If the refractory bricks are damaged, it will not only affect the product quality, but also make the kiln lose its protection, and the kiln must be shut down for maintenance. Once the kiln stops operating, it will cause serious economic losses to the enterprise. Understanding the cause of damage to refractory bricks can * extend their service life, thereby reducing the economic loss caused by shutdown of the kiln for maintenance.
The reasons for the damage of refractory bricks are as follows:
1.The erosion of slag on the brick body*
The erosion of refractory bricks by molten slag mainly includes three processes: penetration, dissolution, and erosion and abrasion. The corrosion of slag on refractory bricks depends on the chemical composition of the slag and refractory materials, operating temperature, and the melting point and fluid state of the slag, including the penetration of the dissolved slag in the refractory material, resulting in structural spalling.
2. Damage caused by thermal stress
Spalling is caused by uneven stress caused by refractory bricks. The reasons include: molten slag penetrates into refractory bricks to form a metamorphic layer, causing structural stress; temperature fluctuations in the kiln cause thermal stress; metal kiln shells cause mechanical stress; refractory bricks for a long time Creep stress generated at high temperature, etc.
Various stresses work together to cause cracks in the weak parts of the brick surface. The cracks continue to expand and penetrate each other to form cracks, leaving the brick body in a flaky or massive form to form flaking, causing damage to the refractory brick.
3. Mechanical wear
The mechanical abrasion of refractory bricks mainly comes from high-speed steam stripping and flowing molten slag, which not only strengthens the chemical reaction between slag and refractory bricks, and removes the reaction products with low ash melting point from the surface of the bricks, but also accelerates the deterioration of the brick body. , The spalling process of the cracked part.
The above are just the basic principles of refractory brick damage. In reality, the actual use of the kiln is different, and it may also cause different degrees of damage to the refractory bricks.
These actual situations include:
The kiln temperature control is too high, and the long-term operation at too high temperature greatly increases the damage rate of the refractory bricks;
The kiln burner nozzle is worn and deformed, causing partial spray, leading to accelerated damage to local refractory bricks;
When the kiln starts and stops, the pressure rises and falls too fast, which will accelerate the falling off of the refractory brick layer, or the heating of the furnace is too fast and repeated flameouts will damage the refractory bricks due to additional stress.
The above is the introduction of knowledge about the damage of refractory bricks.
