JEE Main & Advanced Chemistry Organic Chemistry: Some Basic Principles & Techniques / कार्बनिक रसायन : कुछ मूलभूत सिद्धांत एवं तकन Refractory Materials

The materials which can withstand very high temperatures without melting or becoming soft are known as refractory materials. These are not affected by slags formed during the extraction of metals. These are used in the form of bricks for the internal linings of furnaces. Refractory materials used are of three types,            

(1) Acid refractories : Silica, quartz, silicious sand stones, etc., are the examples.            

(2) Basic refractories : Lime, dolomite, magnesite, etc., are the examples.            

(3) Neutral refractories : Graphite, chromite, bone ash, etc., are the examples.              

Silica \[(92%\ Si{{O}_{2}},\ 2.7%\ A{{l}_{2}}{{O}_{3}})\] and quartz, can tolerate temperatures upto about 1750°C, bauxite upto 1800°C, alumina upto 2000°C and magnesite, chromite, etc., upto 2200°C. Some carbides such as silicon carbide is used as refractory for special purposes.