Machine moulding of dry mixture of refractories requires a pressure of the order of _____________ kg/cm2?

Related Mcqs:

1. Faster rate of drying of moulded refractories results in high _____________ of refractories?

   A. Green strength
   B. Voids
   C. Shrinkage
   D. Both B. and C.

2. Cold crushing strength of ordinary fireclay brick is about 950 kg/cm2. On exposure to a temperature of about 1500°C, its crushing strength may come down to as low as ______________ kg/cm2?

   A. 450
   B. 250
   C. 150
   D. 65

3. Maximum water percentage in refractory mix meant for hand moulding may be as high as _____________ percent?

   A. 2-3
   B. 5-7
   C. 7-12
   D. 14-20

4. Water content in ground refractory material to be shaped into bricks by hand moulding is about ______________ percent?

   A. 5
   B. 20
   C. 40
   D. 55

5. 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

6. Silicon carbide refractories are used in the _____________?

   A. Muffle furnace
   B. Zinc smelting furnace
   C. Ceramic recuperators
   D. All A., B. and C.

7. Except _____________, all other refractories are bad conductors of electricity (i.e, have low electrical conductivity)?

   A. Fireclay
   B. Carborundum
   C. Graphite
   D. Chromite

8. Panel test determines the _____________ of refractories?

   A. Fusion point
   B. Spalling resistance
   C. Slag penetration resistance
   D. Refractoriness under load (RUL)

9. Spray test determines the _____________ of refractories?

   A. Resistance to slag penetration
   B. Resistance to CO attack
   C. RUL
   D. Permanent linear change

10. 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