Roof of a basic open hearth furnace is lined with ______________ bricks?

A. Silica
B. Fireclay
C. Dolomite
D. Magnesite

Chrome magnesite bricks are used in the_________________?

A. Side walls of soaking pits and arc furnaces
B. Copper melting furnaces & converters
C. Burner block of glass tanks
D. All A., B. and C.

Refractory materials are never used in the construction of _________________?

A. Segar cones
B. Orton cones
C. Pressure vessels
D. Ovens & retorts

Graphite or carbon refractories______________________?

A. Exhibit wetting characteristics
B. Should be used in neutral or reducing atmosphere
C. Exhibit high shrinkage on thermal treatment
D. Are not resistant to corrosion by slag

Zirconia refractory_________________?

A. Does not react with basic slags
B. Is produced from baddeleyite
C. Cannot be used as an insulator
D. Has poor electrical conductivity at high temperature

Carbon refractories have very high __________________?

A. Wetting characteristics
B. Refractoriness
C. Thermal conductivity
D. Both B. and C.

An ideal refractory should have high__________________?

A. Spalling rate
B. Fusion point
C. Shrinkage ability
D. None of these

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. Always more than 2500°C

Segar cones are used for the determination of ____________ of refractories?

A. Softening temperature
B. Spalling resistance
C. Electrical conductivity
D. Resistance to slag attack

Porosity is induced in insulating refractories by adding________________?

A. Powdered naphthalene
B. Ammonium chloride/sulphate
C. Calcium phosphate
D. All A., B. and C.