Ceramic fibre

Ceramic fibre is a low thermal mass insulation material, which has revolutionalised the furnace design lining systems.

Ceramic fibre is an alumino silicate material manufactured by blending and melting alumina and silica at temperature of 1800 - 2000 °C and breaking the molten stream by blowing compressed air or drop­ping the melt on spinning disc to form loose or bulk ceramic fibre. The bulk fibre is converted to various products including blanket, strips, veneering and anchored modules, paper, vacuum formed boards and shapes, rope, wet felt, mastic cement etc. for insulation applications.

Fibres are usually produced in two temperature grades based on Al₂O₃ content. A recent addition is ZrO₂ added alumino silicate fibre, which helps to reduce shrinkage levels thereby rating the fibre for higher temperatures. Continuous recommended operating temperature for fibres are given in the following Table 5.8:

TABLE 5.8 CONTINUOUS RECOMMENDED OPERATING TEMPERATURE FOR FIBRES

A12O3 SiO2 ZrO2

1150 °C 43 – 47% 53 – 57% – 1250 °C 52 – 56% 44 – 48% – 1325 °C 33 – 35% 47 – 50% 17 – 20%

These fibres are generally produced in bulk wool form and needled into blanket mass of various densities ranging from 64 to 190 kg/m³. Converted products and over 40 different forms are made from blankets to suit various requirements.