Thermal damage
Overheating phenomenon: The temperature inside the kiln is locally overheated, causing the refractory bricks to melt and form pits. To avoid this situation, the burner should be adjusted correctly and reasonable refractory materials should be selected in different parts.
The phenomenon of thermal shock is caused by sudden temperature changes that generate thermal stress, resulting in peeling and cracking of the brick surface, mainly due to frequent on-off extreme cold and heat. We should stabilize production operations and establish a reasonable system for heating and cooling kilns.
Chemical erosion damage
Alkali corrosion causes gas-phase alkali salt compounds to infiltrate into the voids of the brick and condense and solidify, forming a horizontal infiltration layer of alkali salt in the brick. In production, the content of alkali salt entering the kiln should be reduced.
Under excessive alkali salt erosion, chromium ore reacts with free (K, Na) 2O to form K2 (Na2Cr6). The hexavalent alkali salt produced by the chemical reaction not only damages the brick body, but also pollutes the environment and seriously harms human health. Therefore, the use of magnesia chrome bricks should be reduced and stopped, and replaced with magnesia alumina spinel, magnesia ferrite spinel, dolomite bricks, etc.
The hydration phenomenon of MgO reacts with water to generate Mg (OH) 2, which increases in volume and destroys the overall structure of refractory bricks. Due to the hydration reaction of refractory bricks containing MgO and CaO, it is necessary to ensure that they are stored, transported, and laid in a way that prevents moisture, water, and rain. From the damage mechanism of refractory bricks mentioned above, it can be concluded that standardized construction of refractory materials can effectively extend their service life. Professional, dedicated, and experienced furnace construction is an important link in the use of refractory materials.
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