A. Graphite
B. Magnesite chrome
C. Silica
D. Magnesia
Related Mcqs:
- 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 - For a neutral solution (pH = 7), the value of [H+] [OH-] is equal to_________________?
A. 0
B. 1
C. 1 - In a neutral solution _________________?
A. H+ ions are absent
B. OH- ions are absent
C. Both H+ and OH- ions are present in very small but equal concentration
D. None of these - Which is an acidic refractory ?
A. Magnesite
B. Dolomite
C. Fireclay
D. Chrome magnesite - Which is not an acidic refractory ?
A. Silica
B. Fireclay
C. High alumina refractory
D. Carbon black - Water content in ground refractory material to be shaped into bricks by hand moulding is about _____________ percent?
A. 5
B. 20
C. 40
D. 55 - Addition of zircon to silica refractory brick improves its_________________?
A. Crushing strength
B. Resistance to slag attack
C. Both A. and B.
D. Neither A. nor B. - High porosity refractory bricks have________________?
A. Poor resistance to the penetration of molten slag, metal & flue gases
B. Poor heat conductivity & low strength
C. Better thermal spalling resistance
D. All A., B. and C. - Test piece for determination of RUL of a refractory is heated in a/an__________________?
A. Oxidising atmosphere
B. Reducing atmosphere
C. Electric furnace
D. Neutral atmosphere - Fusion point of a basic refractory material is________________?
A. Reduced by the addition of acid oxides
B. Increased by the addition of acid oxides
C. Not affected by the addition of acid oxides
D. Always less than 1000°C
