Common Causes and Solutions for the Damage of Refractory Castables in Cement Kiln

Refractory castable is widely used in cement industry because of its low production cost and convenient construction.The normal service life is generally more than one year.

Cause analysis of castable damage

1. Castable falls off due to falling off of anchor parts

Anchoring parts can maintain the integrity of castable and increase the anti-bending effect of castable during the use of castable.In places where castable falls off, anchor parts and roots fall off in many places. It is obvious that the castable flakes fall off due to the welding of the raking nail at the welding spot.

2. Rapid damage of castable caused by repeated and drastic changes in temperature

Castables have poor thermal shock stability and are easily damaged by drastic temperature changes.Taking the cooling belt of rotary kiln (especially at the mouth of kiln) as an example, this part is not only continuously eroded by clinker, but also continuously affected by secondary air and high temperature clinker in the kiln. The repeated periodic temperature rise and fall leads to thermal fatigue of the surface layer of castable, which is the cause of castable damage.

3 Construction Reasons

Refractory castables have a set of strict construction requirements, must be required to operate, to ensure good physical properties of castables.If the operation process violates the construction requirements of refractory castable.Without good control of water addition, or without reservation of expansion joints (generally, expansion joints should be kept every 1.5m), it will inevitably cause great damage when heating up.

3.Abnormal operation of kiln

Under other abnormal production conditions such as firing or stopping of kiln and peeling of kiln skin, the rapid temperature change often occurs, resulting in huge internal stress of castable and damage due to thermal fatigue.In addition, the rotary kiln lining is subjected to periodical compression and relaxation due to the huge mechanical stress caused by the large deformation of the cylinder during operation, which will also cause the overall depth damage of the refractory castable.

Measures to solve castable damage

1. Correctly choose the material of anchor parts and welding rod to avoid falling off anchor parts

2.Improve the thermal shock property of castable or adopt castable with better thermal shock stability

3.Improve castable quality, improve heat capacity and reduce temperature fluctuation

4. Improve construction quality