Chemical Refractory Technology Questions Answers - Set 12 - ObjectiveBooks

Chemical Refractory Technology Questions Answers - Set 12

Practice Test: Question Set - 12

1. High thermal conductivity of a refractory material is not important, when it is to be used in the
    (A) Coke oven regenerators
    (B) Muffle furnace
    (C) Blast furnace
    (D) Recuperators

2. Mullite is chemically represented by
    (A) Al2O3. 2SiO2
    (B) 3Al2O3. 2SiO2
    (C) Al2O3. SiO2
    (D) 2Al2O3. 3SiO2

3. Pyrometric cone equivalent (PCE) value (Segar cone) of 'Superduty refractories' is more than 33 which corresponds to a temperature of _________ °C.
    (A) 1520
    (B) 1630
    (C) 1670
    (D) 1730

4. High alumina refractory compared to fireclay bricks have
    (A) Less load bearing capacity
    (B) Less resistance to slag attack
    (C) Low refractoriness
    (D) High resistance to thermal shock and creep

5. Basic bricks are not made of
    (A) Fireclay
    (B) Magnesite
    (C) Forsterite
    (D) Chromite

6. Porosity of fireclay refractories is ________ percent.
    (A) 5-10
    (B) 10-25
    (C) 25-35
    (D) 35-50

7. A steel member used in the furnace construction to take the thrust of the brickwork is called
    (A) Buckstay
    (B) Breast wall
    (C) Armouring
    (D) Baffle

8. Fusion temperature of pure silica (SiO2) is ________ °C.
    (A) 1350
    (B) 1715
    (C) 2570
    (D) 2800

9. Hollow refractory bricks are made by
    (A) Slip casting
    (B) Hand moulding
    (C) Pressing/machine moulding
    (D) Extrusion

10. Bottom of basic open hearth furnace are constructed of
    (A) Dead burnt magnesite ramming mass
    (B) Porous fireclay bricks
    (C) Semi-silica bricks
    (D) Silicon carbide bricks

11. Capacity of a refractory brick to withstand-sudden changes in temperature is denoted by the property called
    (A) Spalling resistance
    (B) Refractoriness
    (C) Refractoriness under load (RUL)
    (D) None of these

12. Addition of zircon to silica refractory brick improves its
    (A) Crushing strength
    (B) Resistance to slag attack
    (C) Both (a) and (b)
    (D) Neither (a) nor (b)

13. Refractoriness/fusion points of 'Superduty' refractories is ________ °C.
    (A) 1520-1630
    (B) 1630-1670
    (C) > 1730
    (D) > 2000

14. Refractories subjected to alternate cycles of heating & cooling are liable to loose their resistance to
    (A) Thermal spalling
    (B) Slag attack
    (C) Fusion under load
    (D) CO attack

15. With increase in the porosity, thermal spalling resistance of fireclay brick
    (A) Increases
    (B) Decreases
    (C) Remain same
    (D) May increase or decrease

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