REFRACTORY

 Protective layers installed inside the kiln or furnace to insulate the furnace steel structure from high temperatures. It also protects it from thermal shocks and chemical attack, and abrasion wears. It may consist of refractory bricks or monolithic refractories such as castable, gunning mixes. The refractory selection depends upon the temperature inside the unit and the chemical nature of the material being processed. The thickness of the lining is generally in the range 80 to 300 mm. The shell must be maintained at low temperature to avoid deformation and also to save energy and protect the plant personnel.