Refractory Technology MCQs

Question 1

An ideal refractory should have high

Accepted Answer

Fusion point

Answer

Spalling rate

Answer

Shrinkage ability

Answer

None of these

Question 2

Pick out the wrong statement.

Accepted Answer

Electrical conductivity of refractory is not important, when these are to be used in electrical furnaces

Answer

Graphite and metals are the good electrical conductor among the refractories and others are all electrical insulators

Answer

Refractories used for lining electrical furnaces should ordinarily have very low electrical conductivity

Answer

Electrical conductivity of porous refractory material is low

Question 3

10 to 30% magnesite is added to chromite to produce chrome-magnesite refractories. Magnesite addition is mainly done to improve the __________ of chromite.

Accepted Answer

Spalling resistance

Answer

Refractoriness

Answer

Crushing strength

Answer

Resistance to slag

Question 4

__________ bricks are used in the burning zone of a cement rotary kiln.

Accepted Answer

High alumina

Answer

Fireclay

Answer

Thoria

Answer

Silicon carbide

Question 5

Spalling of a refractory means its

Accepted Answer

Fracture due to uneven expansion at high temperature

Answer

Softening

Answer

Resistancce to compressive loads

Answer

Resistance to chemical action of gases and molten fluxes

Question 6

Hot metal runner in blast furnace are lined with __________ bricks.

Accepted Answer

Fireclay

Answer

Silica

Answer

Carborundum

Answer

Magnesite

Question 7

Magnesite refractories are generally not used in the

Accepted Answer

Steel melting furnace

Answer

Electric furnace walls

Answer

Open hearth furnace

Answer

Burning zone of cement kilns

Question 8

Fusion point of a basic refractory material is

Accepted Answer

Reduced by the addition of acid oxides

Answer

Increased by the addition of acid oxides

Answer

Not affected by the addition of acid oxides

Answer

Always less than 1000°C

Question 9

Fireclay bricks are used in the

Accepted Answer

All of the above

Answer

Furnaces allowed to cool frequently

Answer

Flues

Answer

Chimney linings