Refractory Technology MCQs

Question 1

Magnesite refractories have low resistance to

Accepted Answer

Both B and C

Answer

Attack by basic slag

Answer

Abrasion

Answer

Disintegration on sudden change of temperature

Question 2

Refractoriness of a typical silica brick corresponds to Segar cone number, '32', which is equivalent to a temperature of __________ °C.

Accepted Answer

1710

Answer

1380

Answer

1520

Answer

1915

Question 3

Refractory bricks having lower porosity have

Accepted Answer

Greater strength

Answer

High insulating properties

Answer

Low heat capacity

Answer

Low thermal conductivity

Question 4

Fireclay refractories have

Accepted Answer

Low co-efficient of thermal expansion

Answer

Poor thermal spalling resistance

Answer

Tendency to expand unduly high during firing

Answer

Very high cost

Question 5

RUL of refractories depends on the

Accepted Answer

All of the above

Answer

Chemical composition

Answer

Physical structure

Answer

Presence of impurities like iron & alkali

Question 6

Which of the following is not an acidic refractory?

Accepted Answer

Magnesia bricks

Answer

Silica bricks

Answer

Fireclay bricks

Answer

Bauxite bricks

Question 7

Which of the following has the lowest electrical resistivity?

Accepted Answer

Graphite

Answer

Fireclay

Answer

Alumina

Answer

Zircon

Question 8

Periclase refractory contains mainly

Accepted Answer

MgO

Answer

CaO

Answer

Al 2 O 3

Answer

SiO 2

Question 9

Magnesite chrome refractories

Accepted Answer

Have better spalling resistance than chrome magnesite refractories

Answer

Have very low thermal co-efficient of expansion

Answer

Are not at all resistant to the corrosive action of iron oxide

Answer

Have very low (50 kg/cm 2 ) cold crushing strength (C.C.S.) and can not be used in metalcase form