Chemical Engineering Refractory MCQ - Set 02 - ObjectiveBooks

Chemical Engineering Refractory MCQ - Set 02

Practice Test: Question Set - 02

1. Chromite refractories are used in
    (A) Bottom of soaking pits
    (B) Between acid & basic linings in basic open hearth furnaces to prevent their chemical action with each other
    (C) Both (a) & (b)
    (D) Neither (a) nor (b)

2. The linear thermal expansion of __________ bricks upto 1000 °C is very low of the order of ≤ 0.5 percent.
    (A) Fireclay
    (B) Silica
    (C) Magnesite
    (D) Corundum

3. Maximum apparent porosity of magnesite bricks is about __________ percent.
    (A) 8
    (B) 24
    (C) 44
    (D) 58

4. Chrome magnesite is not used in the
    (A) Inner lining of L.D. converter
    (B) Aluminium melting furnaces
    (C) Wear out lining of steel melting furnaces
    (D) All (a), (b) and (c)

5. Cold crushing strength of refractories depends upon its
    (A) Composition
    (B) Texture
    (C) Firing temperature
    (D) All (a), (b) and (c)

6. ________ bricks are used in the burning zone of a cement rotary kiln.
    (A) High alumina
    (B) Fireclay
    (C) Thoria
    (D) Silicon carbide

7. Pick out the wrong statement.
    (A) Fluxing material like lime is added in clay to reduce the vitrification temperature
    (B) Main constituents of clay are alumina and silica
    (C) Addition of sand in ceramic materials makes it non-plastic, increases its fusion point and reduces its shrinkage on burning
    (D) Vitrification of fireclay material is done to increase its porosity

8. 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

9. Which property is important for bricks used in the combustion chamber & dome of blast furnace stoves?
    (A) High refractoriness
    (B) High resistance to spalling
    (C) High strength and density
    (D) All (a), (b) and (c)

10. Which of the following has the lowest electrical resistivity?
    (A) Graphite
    (B) Fireclay
    (C) Alumina
    (D) Zircon

11. Spalling resistance of a refractory cannot be increased by
    (A) Increasing its porosity
    (B) Using a coarser grog during its manufacture
    (C) Decreasing its thermal co-efficient of expansion
    (D) Making it denser

12. Refractory castables are used for
    (A) Producing monolithic linings
    (B) Patch work
    (C) Minimising the number of joints in the structure
    (D) All (a), (b) and (c)

13. High refractoriness of refractory bricks means, that it has a
    (A) High spalling resistance
    (B) Low spalling resistance
    (C) High resistance to fusion
    (D) Low porosity

14. Silicon carbide refractories have very low
    (A) Refractoriness (< 1700°C)
    (B) Thermal conductivity
    (C) Resistance to thermal shock
    (D) None of these

15. To resist spalling tendency, a refractory should have
    (A) Greater diffusivity
    (B) Low specific heat
    (C) Low thermal co-efficient of expansion
    (D) All (a), (b) and (c)

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