Refractory Technology MCQs

Question 1

With increasing alumina content, the fusion point of high alumina refractories

Accepted Answer

Increases

Answer

Decreases

Answer

Remains constant

Answer

May increase or decrease ; depends on its alumina content

Question 2

Rate of slag attack on refractories increases with rise in temperature due to the

Accepted Answer

Decreased viscosity of slag

Answer

Increased thermal conductivity of brick

Answer

Oxidising condition in the furnace

Answer

None of these

Question 3

Ganister is a source of the

Accepted Answer

Silica

Answer

Periclase

Answer

Lime

Answer

None of these

Question 4

Zirconia refractories are not used in

Accepted Answer

Furnaces subjected to fluctuating temperature

Answer

Making sheaths for thermocouple

Answer

Lining high temperature ceramic kilns

Answer

High frequency induction furnaces in the form of inductors

Question 5

Spalling tendency of refractories is reduced by increasing its

Accepted Answer

Porosity

Answer

Specific gravity

Answer

Thermal conductivity

Answer

Strength

Question 6

Cold crushing strength of a refractory does not depend upon its

Accepted Answer

Shape

Answer

Composition

Answer

Firing temperature

Answer

Texture

Question 7

'Spinel', a refractory mineral is chemically represented as

Accepted Answer

M g Al 2 O 4

Answer

M g Al 2 O 3

Answer

M g SO 4

Answer

M g Al 2 O 3 .2H 2 O

Question 8

Machine moulding of dry mixture of refractories requires a pressure of the order of __________ kg/cm².

Accepted Answer

1000

Answer

10

Answer

100

Answer

500

Question 9

Bauxite calcining rotary kilns are lined with __________ bricks.

Accepted Answer

85% alumina

Answer

Fireclay

Answer

Carbon

Answer

Corundum