Related Questions

Faster rate of drying of moulded refractories results in high __________ of refractories.
A Green strength
B Voids
C Shrinkage
D Both B and C
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
Porosity is induced in insulating refractories by adding
A Powdered naphthalene
B Ammonium chloride/sulphate
C Calcium phosphate
D All of the above
A steam carraying pipeline is insulated with two layers of insulating materials with the inferior insulation material forming the inner part. If the two insulating layers are interchanged, the heat conducted will
A Increase
B Decrease
C Remain unaffected
D May increase or decrease; depends on the thickness of each layer
Refractories used in/for __________ should have low thermal conductivity.
A Coke ovens
B Insulation
C Regenerators
D Muffle furnaces
Furnace atmosphere for softening temperature determination of refractories (in which segar cones are placed) should be
A Oxidising
B Neutral
C Either A or B
D Neither A nor B
Except __________ , all other refractories are bad conductors of electricity (i.e, have low electrical conductivity).
A Fireclay
B Carborundum
C Graphite
D Chromite
Magnesite refractories have low resistance to
A Attack by basic slag
B Abrasion
C Disintegration on sudden change of temperature
D Both B and C
Fireclay refractories have
A Low co-efficient of thermal expansion
B Poor thermal spalling resistance
C Tendency to expand unduly high during firing
D Very high cost
silicon carbide refractories have very low
A [

A. Refractoriness (

B. Thermal conductivity

B Resistance to thermal shock
C None of these

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