Ceramic recuperators used for waste heat recovery from high temperature flue gas going out of the furnace is made of________________?

Related Mcqs:

1. Cermets are combination of ceramic and metallic materials due to which they have high strength & resistance to high temperature. Cermets are used in the_______________?

   A. Hearth of the blast furnace
   B. Nuclear reactors, missiles & space crafts
   C. Insulation of high temperature furnaces
   D. Roof of electric furnaces

2. Most Cermets, which normally have high thermal conductivity and high thermal shock resistance, comprises of ceramic & metallic components of ______________ percent respectively?

   A. 80 and 20
   B. 20 and 80
   C. 50 and 50
   D. 60 and 40

3. Because of its very high refractoriness of the order of __________ °C, silicon carbide refractories are used in zinc smelting furnace, muffle furnace and for supporting the wares in tunnel kilns ?

   A. 1800
   B. 2200
   C. 2400
   D. 2700

4. Ferromagnetic ceramic material is not used in the__________________?

   A. Thermal insulation
   B. Transformers
   C. Magnetic switches
   D. Television sets

5. Furnace atmosphere for softening temperature determination of refractories (in which Seger Cones are placed) should be __________________?

   A. Oxidising
   B. Neutral
   C. Either A. or B.
   D. Neither A. nor B.

6. Maximum alumina content in high alumina refractory can be as high as _____________ percent?

   A. 30
   B. 50
   C. 70
   D. 90

7. Thermal diffusivity of a refractory brick is high, when its ____________ is high?

   A. Density
   B. Specific heat
   C. Thermal conductivity
   D. None of these

8. Pure bauxite is the best raw material for the manufacture of high alumina refractories, in which maximum alumina content can be as high as _____________ percent?

   A. 55
   B. 70
   C. 80
   D. 90

9. Silica bricks are attacked by basic slags at high temperature. Which of the following is not used solely as a binding material ?

   A. Aluminium phosphate
   B. Water
   C. Lime
   D. Plaster of Paris

10. Beryllia (which is used in making crucibles for melting uranium & thorium) is superior to alumina in all respects for high temperature (> 1900°C ) use, except ?

    A. Cost
    B. Electrical conductivity
    C. Thermal conductivity
    D. Fusion point