Light Insulaing FireBrick whose full name is mullite insulating firebrick, was created in last century. Since it was invented light weight insulating firebrick has been a kind of widely used industrial insulation product ,it has solved two big problems in high temperature industry named high-temperature erosion and hemical attack , so till now the light weight insulating firebrick manufacturing and application still has a strong development momentum..
As regards to its application, firstly it is used as a high temperature insulating layer. Secondly it is used at the hot surface as a back lining in the heat treatment equipments. Thirdly light weight insulating firebrick can reduce the thermal heat loss between two thermal layers and avoid the heat released directly to the air. Why it can do this ?
1.Internally generated heat circulation which reduces the heat conduction
2.As it is a kind of low density material, its heat storage is low , this property can reduce the heat loss.
In the beginning, light weight insulating firebrick is widely used on periodic or cyclical heat treatment equipment , such as the down draft kilns, shuttle kilns. And then it is gradually used in tunnel kilns and metallurgical blast furnace maturely. Obviously it has advantage of high insulation properties and reducing the thickness of the furnace wall & the construction cost.
The name of light weight insulating firebrick is just compared to dense refractory bricks, the biggest difference with dense bricks is that light weight insulating firebrick is added some filler in, and then the fillers will be fully combusted at a high temperature condition, some pores will be formatted inside the bricks. This close pores are the best way of insulation and non conductors. The gaps between irregular pores makes the heat conduction path more and more tortuous and difficult..
We may notice that there are many kinds of fillers could be used in the production of the insulating firebrick, like flammable, volatile materials, sawdust, cork, polystyrene ball, paper scraps, water. Most widely used in China is the polystyrene and sawdust.
According to the molding way the production methods could be classified to be following categories :
- forged hand-formed, mostly used in the manually production.
- pressure molding machine, which is widely used.
- rejection of the material
- casting method