Insulation materials are always used as the insulation layer and lining of heating furnaces. It can reduce heat loss and save energy. There are a variety of insulation materials, including lightweight refractory products, insulation monolithic materials and refractory fiber products. 

The roofs of the heating zone and soaking zone are constructed with high alumina hanging brick, with a layer of insulation board laid over it. The wall is successively constructed with high alumina brick, fire clay brick, fire clay insulation brick and insulation board. The bottom of heating zone is constructed with magnesia chrome brick, magnesia brick, fire clay brick, fire clay insulation brick and insulation board. The lining of the preheating zone is constructed with fire clay brick. Recently, more and more refractory castables are used in the heating furnace. High alumina cement, refractory castables, clay bonding refractory castables and lightweight casting materials is used in the lining. 

Lightweight refractory products mainly include silica insulation brick, fire clay insulation brick, high alumina insulating brick and alumina bubble brick. The bulk density of lightweight refractory products is generally 0.6-1.2g/cm3. Its service temperature is 900-1350℃. alumina bubble brick can be used below 1800℃ for a long time. 

Refractory fiber is a type of new efficient fibrous refractory insulation material. The main manufacturing methods include Melting-blowing method, high-speed centrifugation method and colloidal method. 

Refractory fiber products mainly include ceramic fiber, zirconia ceramic fiber, high-purity high alumina ceramic fiber, polycrystalline mullite fiber, alumina fiber and zirconia fiber. Besides, materials for low temperature insulation include slag wool and glass fiber. 

Refractory fiber products have low bulk density, low thermal conductivity, good thermal stability and mechanical shock resistance. It is soft and easy to cut and construct. Using refractory fiber as the lining can effectively reduce heat loss, save energy and rise the temperature.