A. Diatomaceous earth/kieselgur
B. Asbestos
C. Vermiculite
D. None of these
Related Mcqs:
- Porosity is induced in insulating refractories by adding________________?
A. Powdered naphthalene
B. Ammonium chloride/sulphate
C. Calcium phosphate
D. All A., B. and C. - Insulating refractories should have_______________?
A. High porosity
B. Low thermal conductivity
C. Both A. and B.
D. Neither A. not B. - Hot face insulating linings of high purity alumina fused mullite are used, where_________________?
A. Very high temperatures are involved
B. Highly reducing conditions are involved
C. Presence of iron or silica is harmful
D. All A., B. and C. - Which is required in an insulating refractory ?
A. High thermal conductivity
B. Low porosity
C. Both A. and B.
D. Neither A. nor B. - Natural silica___________________?
A. Mainly contains quartz
B. Is not stable at high temperature
C. Transforms to other allotropic forms i.e. Tridymite and Cristobalite involving very high
volume changes
D. All A., B. and C. - 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 - Ferromagnetic ceramic material is not used in the__________________?
A. Thermal insulation
B. Transformers
C. Magnetic switches
D. Television sets - Mixing of ground refractory material and water is done in a ______________ mill?
A. Pug
B. Ball
C. Tube
D. Rod - High thermal conductivity of a refractory material is not important, when it is to be used in the______________________?
A. Coke oven regenerators
B. Muffle furnace
C. Blast furnace
D. Recuperators - Pure bauxite is the best raw material for the manufacture of high alumina refractories, in which maximum alumina content can be as high as _____________ percent?
A. 55
B. 70
C. 80
D. 90
