Refractory Technology Computer Based Online Test - Set 14 - ObjectiveBooks

Refractory Technology Computer Based Online Test - Set 14

Practice Test: Question Set - 14

1. Fireclay bricks are not used in the
    (A) Blast furnace
    (B) Hot blast stove
    (C) Cupola
    (D) Wall of coke oven

2. An insulating refractory brick should have high porosity and low thermal conductivity. Which of the following is not used for inducing porosity in the insulating refractory bricks during its manufacture?

    (A) Cork
    (B) Saw dust
    (C) Sand
    (D) Chemically prepared foam

3. Permeability of bricks is a measure of the

    (A) Refractoriness
    (B) Melting point
    (C) Rate at which a fluid will pass through the pores
    (D) Expansion during heating

4. Magnesite refractories are used for the construction of those furnaces, which are
    (A) Not required to resist the corrosive action of basic slag
    (B) Not subjected to fluctuation in temperature
    (C) Used for raising & maintaining high temperature
    (D) Both (b) and (c)

5. Pick out the wrong statement.

    (A) Insulating refractories used in place of regular refractory bricks are usually called light weight refractories, and they have similar composition as heavy bricks
    (B) Graphite refractories are also called plumbago refractories
    (C) Superduty fireclay bricks correspond to a pyrometric cone equivalent of 26-28
    (D) Calcined magnesite is also called dead burnt magnesite

6. Outer combustion chamber of blast furnace stove is lined with __________ bricks.

    (A) Fireclay
    (B) Silica
    (C) Chrome magnesite
    (D) Zirconia

7. Carborundum used for making crucibles for melting non-ferrous metals is chemically

    (A) Silicon carbide
    (B) Silicon nitride
    (C) Crystalline magnesia
    (D) Zirconium sulphate

8. Roof of a basic electric furnace is made of __________ bricks.

    (A) Superduty fireclay
    (B) Silica
    (C) Chromite
    (D) None of these

9. Faster rate of drying of moulded refractories results in high __________ of refractories.

    (A) Green strength
    (B) Voids
    (C) Shrinkage
    (D) Both (b) and (c)

10. Which property of refractories is the most important for top section of the blast furnace?

    (A) Resistance to abrasion
    (B) Resistance to slag penetration
    (C) Stability of volume at high temperature
    (D) Resistance to corrosion by slag

11. Refractories used in/for _________ should have low thermal conductivity.
    (A) Coke ovens
    (B) Insulation
    (C) Regenerators
    (D) Muffle furnaces

12. Spalling of silica bricks occurs due to abrupt volume changes, when it is cooled below a temperature of _________ °C.

    (A) 770
    (B) 570
    (C) 270
    (D) 70

13. Lower wall courses of soaking pits are made of __________ bricks to avoid the action of molten slag & scale.

    (A) Chrome or magnesite
    (B) Silicon carbide
    (C) Silica
    (D) Low duty fireclay

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