Refractories are heat resistant materials used in almost all processes involving high temperatures and /or corrosive environments. These are typically used to insulate and protect industrial furnaces and vessels due to their excellent resistance to heat, chemical attack and mechanical damage. A proper refractory can ensure no loss of production time and the equipment. The various types of refractories also influence the safe operation, energy consumption and product quality: therefore obtaining refractories best suited to each application is of supreme importance.
Refractories as “…non-metallic materials having those chemical and physical properties that make them applicable for structures, or as components of systems, that are exposed to environments above 1,000 °F (811 K; 538 °C).”
Refractory materials are used in linings for Furnaces, Kilns, Incinerators, and Reactors. They are also used to make Crucibles and moulds for casting glass and metals and for surfacing flame deflector systems for rocket launch structures. Today, the Iron & Steel Industry uses approximately 70% of all refractories produced.
Based on fusion temperature :
Based on Fusion Temperature (melting point) refractory materials are classified into three types.
- Normal refractory: Fusion temperature of 1580 ~ 1780 °C (e.g. Fire clay)
- High refractory: Fusion temperature of 1780 ~ 2000 °C (e.g. Chromite)
- Super refractory: Fusion temperature of > 2000 °C (e.g. Zirconia)
Based on the method of manufacture :
Dry press process
- Fused cast
- Hand moulded
- Formed (normal, fired or chemically bonded)
- Un-formed (monolithic-plastic, ramming and gunning mass, castables, mortars, dry vibrating cement.)
- Un-formed dry refractories.
Types of Refractory :
- Refractory Fire bricks
- Refractory Insulation Bricks
- Refractory Castables
- Insulation Castables
- Refractory Mortar