Why the lining of boiler furnace is required?

Lining with fire-resistant, wear-resistant, and also heat-insulating materials which cover an internal surface of boiler is made for protection of surfaces against possible mechanical, thermal and chemical damages of steel surfaces of the boiler.
Also, the lining of the boiler furnace is designed to reduce heat loss and allows you to maintain a sufficient temperature for efficient fuel combustion.
Heat-resistant concrete and bricks are used for lining that can withstand temperatures up to 1200 – 1400 ° C.