Selection criteria for refractory insulating bricks (IFB)
Interface temperature of refractory and backing insulation
When IFB is used as the insulating material of refractory brick backing, the interface temperature between refractory brick and IFB backing material must be fully considered to determine the type and type of IFB. The IFB that allows the operating temperature to be higher than the interface temperature must be selected. At the same time, considering that the working environment of the working lining is very bad, it is often eroded by flying dust, slag with dust accumulation and other factors, leading to corrosion and quality decline, which will inevitably lead to the rise of interface temperature. When designing the IFB backing, the user must consider the wear of the working lining. In order to achieve this goal, IFB must be carefully selected to ensure the service life of IFB backing when the interface temperature rises. Our IFB products ensure minimum shrinkage and long continuous use. Therefore, it is recommended to select IFB whose working temperature is more than 100℃ higher than the interface temperature.
Atmospheric corrosion
When IFB is used for heat treatment, in addition to the interface and furnace working temperature, there is also an important factor is the harmful influence of furnace atmosphere on the furnace lining. During heat treatment, CO, H2 and decomposed ammonia (N2+H2) are usually used to prevent the product from peeling. When these gases contact the furnace lining, they will cause undesirable corrosion, so they must be selected correctly to adapt to different land lines. For example, IFB with low iron oxide content and high aluminum content should be selected in the reduction atmosphere furnace. Compared with air, the heat conductivity of hydrogen is much higher, and the heat loss of furnace lining is large. It is recommended to use special alumina bricks.
Furnace working temperature
When IFB is selected as the refractory working face, the maximum working temperature of the furnace is the main factor determining the type of IFB. The operating temperature of IFB must be 100-300℃ higher than the furnace operating temperature
