Which is an acidic refractory?

An insulating refractory brick should have high porosity and low thermal conductivity. Which of the following is not used for inducing porosity in the insulating refractory bricks during its manufacture?

A

Cork

B

Saw dust

C

Sand

D

Chemically prepared foam

Dry mix hydraulic compositions of refractory aggregates with suitable bonding materials are called refractory

A

Mortars

B

Cements

C

Castables

D

None of these

If a refractory contains high content of silicon, it means refractory is

A

Acidic

B

Basic

C

Neutral

D

Brittle

Which is not an acidic refractory?

A

Silica

B

Fireclay

C

High alumina refractory

D

Carbon black

Which of the following is not an acidic refractory?

A

Silica bricks

B

Fireclay bricks

C

Bauxite bricks

D

Magnesia bricks

Fusion point of an acidic refractory material is

A

Increased by the addition of basic oxides

B

Reduced by the addition of basic oxides

C

Not affected by the addition of basic oxides

D

Not affected by the addition of basic oxides

Which of the following is not a high alumina refractory material?

A

Kyanite

B

Sillimanite

C

Diaspore

D

Periclase

Which of the following will happen if the thickness of refractory wall of furnace is increased?

A

Heat loss through furnace wall will increase

B

Temperature inside the furnace will fall

C

Temperature on the outer surface of furnace walls will drop

D

Energy consumption will increase

Ceramic coating material for furnace refractory, which increases its emissivity and thus the radiation heat transfer rate in the furnace, comprises of

A

Graphite powder

B

Thoria

C

Zircon powder

D

Beryllium

Which is required in an insulating refractory?

A

High thermal conductivity

B

Low porosity

C

Both A & B

D

Neither A nor B

Which is an acidic refractory?

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