Refractories are used at elevated temperatures for structural purposes and they are used in many cases to contain a high temperature corrosive environ ment. In any process environment, refractories are potentially continuously under attack from a number of corrosive processes.
The corrosion environment usually contains materials and byproducts of the process in chemical reactions with the refractory at elevated temperatures resulting in refractory consumption or wear, potentially causing glassing o r softening of the refractories. It is usually not immediately obvious, but the oxidation and reduction state of the environment can participate in an d influence the chemical reactions that take place. Along with chemical rea ction during corrosion, physical changes occur that may be accelerated by t he corrosion process.
Erosion is another prevalent refractory wear mechanism. Refractories can be worn away over time from the washing action of moving liquids, such as mol ten metals or slags. Erosion further exposes refractory to destruction by c orrosive or abrasive elements.
Abrasive media, including fuel, ash, and other particles, can wear away ref ractories over time, much like sandblasting. Refractory resistance against abrasion is a key issue for many industrial furnace applications.
Moving parts and equipment within a process can wear against the refractory lining, jeopardizing the structural integrity of the refractory lining.
As refractories undergo the heating and cooling cycles of a process, the re fractories expands and contracts, eventually weakening and wearing down the lining. If refractories experiences a rapid change in temperature, a.k.a T hermal Shock, the refractories can experience immediate damage.
As a result of the high temperature corrosive environment, refractories wil l wear down over time, requiring periodic maintenance and eventual replacem ent. Refractory wear can be mitigated or minimized by selecting the right r efractories to withstand the corrosive environments.