Abrasion is the destructive process that causes a material to wear away through mechanical scraping or scratching. Refractory material is designed to be very durable, withstand extreme service conditions and defy mechanical abuse in many different types of thermal-processing operations.
However, severe conditions that cause abrasion in the form of high levels of mechanical scraping and airborne particulate matter can challenge refractories, shortening their service lives.
Understanding abrasion can be the key to extending the life of your refractory lining.
Once abrasion is identified as the main mode of failure, there are several options to counter it. Selecting a refractory material based on a raw material hard enough to resist the abrasion is a common technique. For one material to abrade another it must be harder than the material being abraded. For instance, a diamond can be used to scratch glass, but glass cannot be used to scratch a diamond.
It follows that refractory materials based on very hard raw materials, like silicon carbide, can be used to resist abrasion and extend the life of the lining. It should be remembered, however, that a refractory lining is made up of many different materials, not just the main constituent raw materials. Clay, cement, silica and other softer components will still be exposed and abraded even if abrasion of the main aggregate is stopped completely.
Another option is to investigate the source of the abrasion and make adjustments to the process:
- using a less-abrasive cleaning tool
- limiting the contact of the abrading process materials with the refractory lining
- adjusting the angle between the refractory lining and the incoming airborne particulate.
A minor change in the process, with minimal cost and no downsides to the operation can save in refractory replacement costs. When changes to the process are not an option, it is best to consider the abrasion resistance of the lining as a whole and select a specifically designed abrasion-resistant solution.
A qualified, knowledgeable refractory solution expert with genuine experience will help you make the best decision for your specific application, taking into consideration the following:
- Speed of installation
- Service life
- All-in price