The service life of firebrick is mainly affected by the following factors:
1. Operating temperature
– Firebrick has its fire resistance limit, when the working temperature is close to or exceeds its fire resistance for a long time, it will lead to softening, deformation and even melting of the firebrick. For example, ordinary clay firebricks have a refractoriness of 1580-1750 ° C, and if they are used in an environment higher than this temperature range for a long time, their structure will be destroyed. Moreover, frequent and large temperature changes will produce thermal stress and reduce the service life of refractory bricks with poor thermal shock resistance.
2. Chemical attack
– Chemicals in the environment will react with firebricks. For example, in glass melting kiln, the alkali metal oxide in the glass liquid will erode the refractory brick on the wall of the melting part. In the metallurgical furnace, the pH of the slag will also cause corrosion to the refractory brick. Acid slag will eat the basic firebrick, and the basic slag will eat the acid firebrick.
3. Mechanical wear
– Material flow, erosion and vibration during equipment operation will cause mechanical wear. In the combustion chamber of CFB boiler, fuel particles and high-speed air flow will continuously wash the refractory bricks on the furnace wall. In a cement rotary kiln, the flow of high temperature clinker can also wear down the refractory bricks on the kiln walls.
4. Brick body quality
– Factors such as raw material purity and production process determine the quality of refractory bricks. Refractory bricks with high purity and less impurities have better performance. For example, high purity fused zirconium corundum brick in the glass furnace erosion resistance is stronger than the more impurities of the same brick. Moreover, the porosity of the brick body is also critical, and the low porosity of the refractory brick can better resist the penetration of liquids and gases, reducing erosion.
5. Construction quality
– The way and quality of masonry of refractory bricks affect their service life. If the brick seam is too large, it is easy to let melt or corrosive gas penetrate, and accelerate the damage of the brick. At the same time, the bond between bricks and bricks is not strong, and it is easy to fall off when subjected to external force or thermal stress.
6. Operating conditions of the device
– Unreasonable operation will shorten the service life of the firebrick. For example, in the heating and cooling process of the kiln, if the speed is too fast, the refractory brick will be damaged due to excessive thermal stress; In metallurgical furnaces, frequent changes in the atmosphere of the furnace will also have adverse effects on refractory bricks.
