A. Are wetted by molten iron
B. Are used in the hearth of blast furnace
C. Are acidic in nature
D. All A., B. and C.
Related Mcqs:
- ____________ of carbon blocks in the hearth of blast furnace helps in avoiding skull formation, when it becomes cold?
A. High thermal conductivity
B. Low porosity
C. Non-wetting characteristics
D. High density - Skull is not formed on the carbon blocks in the hearth of a blast furnace, when it becomes cold, because of its_______________?
A. Non-wetting characteristic
B. High thermal conductivity
C. High crushing strength
D. None of these - Sillimanite (Al2O3.SiO2) refractory, which is a neutral refractory, is not used in________________?
A. Pottery furnace
B. Glass melting furnace
C. Crucibles
D. Gas retorts - ___________________ is the measure of the strength of refractory under the combined effect of temperature & load ?
A. Porosity
B. RUL
C. Specific gravity
D. Thermal conductivity - Refractory materials are never used in the construction of _________________?
A. Segar cones
B. Orton cones
C. Pressure vessels
D. Ovens & retorts - Which of the following is not a neutral refractory ?
A. Silicon carbide
B. Magnesite
C. Chromite
D. Graphite - Resistance to slag attack of a refractory _____________________?
A. Depends on the nature of slag & refractory
B. Decreases at higher temperature
C. Decreases, if defective joints & cracks exist in the refractory
D. All A., B. and C. - 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 - Dry mix hydraulic compositions of refractory aggregates with suitable bonding materials are called refractory_________________?
A. Mortars
B. Cements
C. Castables
D. None of these - Refractory bricks having lower porosity have_________________________?
A. High insulating properties
B. Low heat capacity
C. Low thermal conductivity
D. Greater strength
