Classifications and Some Words About Quality Control

1 Classifications and Some Words About Quality Control 

There are small differences in different classifications of refractory materials among ISO, DIN, and ASTM standards [1 ]. The most common definition is that refractories are shaped and unshaped materials that are durable at high temperature ( 1,500 °C). Usually, heat refractory insulation materials have a service temperature of 800-1,100 °C. 

The term refractories for Al industry is relatively young. Initially, Al producers didn t pay much attention to special requirements of refractories. The exceptions were carbon cathode materials, which should be electroconductive. 

One characteristic of a refractory is the mineral composition. In the Al industry, the most common are alumina silica refractories, carbon, and silicon carbide refractories. 

Some words about carbon materials. Historically, the production of carbon materials has stood apart from the refractory industry, having many commonalities. The producers and researchers of carbon materials introduced several characteristics specific for the refractory industry and do not like the use of term carbon refractories when one refers to carbon cathode materials. Yet we will use the term carbon refractories, taking into account the peculiarities of carbon materials, because it is a material for refractory application, as it can withstand the corrosive interaction of liquid media at high temperatures over a long period. 

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