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.
Related Mcqs:
- Maximum alumina content in high alumina refractory can be as high as _____________ percent?
A. 30
B. 50
C. 70
D. 90 - 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 - With increase in the alumina content, the refractoriness of high alumina refractories_______________?
A. Increases
B. Decreases
C. Remain same
D. May increase or decrease - With increasing alumina content, the fusion point of high alumina refractories__________________?
A. Increases
B. Decreases
C. Remain constant
D. May increase or decrease; depends on its alumina content - Upper portion of hot metal mixer are lined with mullite bricks, which helps in resisting the_________________?
A. Washing action of metal
B. Corrosion by layer of slag
C. Both A. & B.
D. Neither A. nor B. - Chemically, mullite refractories is____________________?
A. 3Al2O3.2SiO2
B. Al2O3
C. ZrSO4
D. ThO2 - Mullite is chemically represented by_________________?
A. Al2O3. 2SiO2
B. 3Al2O3. 2SiO2
C. Al2O3. SiO2
D. 2Al2O3. 3SiO2 - High alumina refractories are used in the ___________________?
A. Dome of blast furnace stoves
B. Electric arc furnace roof
C. Glass melting furnaces
D. All A., B. and C. - Which is not a high alumina refractory ?
A. Mullite
B. Corundum
C. Bauxite
D. Dolomite - High alumina refractory compared to fireclay bricks have____________________?
A. Less load bearing capacity
B. Less resistance to slag attack
C. Low refractoriness
D. High resistance to thermal shock and creep
