Refractory Technology MCQs

Question 1

Capacity of a refractory brick to withstand-sudden changes in temperature is denoted by the property called

Accepted Answer

Spalling resistance

Answer

Refractoriness

Answer

Refractoriness under load (RUL)

Answer

None of these

Question 2

With increase in the alumina content, the refractoriness of high alumina refractories

Accepted Answer

Increases

Answer

Decreases

Answer

Remains same

Answer

May increase or decrease

Question 3

Bottom of basic open hearth furnace are constructed of

Accepted Answer

Dead burnt magnesite ramming mass

Answer

Porous fireclay bricks

Answer

Semi-silica bricks

Answer

Silicon carbide bricks

Question 4

Zircon refractories have

Accepted Answer

All of the above

Answer

Low co-efficient of expansion

Answer

High RUL (1600°C) and refractoriness (> 2000°C)

Answer

High spalling resistance

Question 5

Fireclay bricks are never used in the

Accepted Answer

Coke oven walls

Answer

Beehive oven

Answer

Zinc roaster

Answer

Lead blast furnace

Question 6

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.

Accepted Answer

90

Answer

55

Answer

70

Answer

80

Question 7

High porosity refractory bricks have

Accepted Answer

All of the above

Answer

Poor resistance to the peneration of molten slag, metal & flue gases

Answer

Poor heat conductivity & low strength

Answer

Better thermal spalling resistance

Question 8

Upper portion of hot metal mixer are lined with mullite bricks, which helps in resisting the

Accepted Answer

Washing action of metal

Answer

Corrosion by layer of slag

Answer

Both A & B

Answer

Neither A nor B

Question 9

Which of the following is not a neutral refractory?

Accepted Answer

Magnesite

Answer

Silicon carbide

Answer

Chromite

Answer

Graphite