The adhered corundum layer is initially soft and can be easily removed, but in later stages the product is dense, hard and difficult to remove during cleaning and can cause mechanical damage to the lining during removal.
So , it is evident that the accumulation of corundum is one of the main factors influencing energy consumption, because the growth of corundum reduces the capacity of the hearth furnace and the thermal conductivity in walls also its reduces the furnace life due to differential thermal behavior.

corundum re-growths.

The growth of corundum requires intensive cleaning of the liner with cleaning fluxes and mechanical tools that cause wear of the hot face liner and consequent loss of heat in the furnace.

The use of some refractory materials can also help to reduce the formation of corundum; in general, phosphate bonded materials show excellent resistance to aluminium metal penetration and corundum growth.