A. Are bonded with lime and clay
B. (Free from silica) have better thermal fatigue resistance than silica and magnesite refractories.
C. Are resistant to basic slag
D. All A., B. and C.
Related Mcqs:
- 10 to 30% magnesite is added to Chromite to produce chrome-magnesite refractories. Magnesite addition is mainly done to improve the _____________ of Chromite?
A. Spalling resistance
B. Refractoriness
C. Crushing strength
D. Resistance to slag - Carbon refractories_____________________?
A. Do not burn/oxidise, when exposed to air on heating
B. Are not attacked by slags, as they are not wetted by melts
C. Do not resist temperature fluctuations
D. Have extremely low thermal & electrical conductivities - Chromite refractories are used in_______________?
A. Bottom of soaking pits
B. Between acid & basic linings in basic open hearth furnaces to prevent their chemical action
with each other
C. Both A. & B.
D. Neither A. and B. - Chromite refractories are_____________________?
A. Acidic refractory
B. Neutral refractory
C. Basic refractory
D. Fired at a temperature of 600°C only - Maximum water percentage in refractory mix meant for hand moulding may be as high as _____________ percent?
A. 2-3
B. 5-7
C. 7-12
D. 14-20 - Which one expands on heating ?
A. Silica bricks
B. Fireclay bricks
C. Both A. & B.
D. Neither A. nor B. - Which refractory must have controlled atmosphere (temperature and humidity) for its safe storage ?
A. Tar bonded dolomite bricks
B. Fireclay bricks
C. Mullite bricks
D. Magnesite bricks - Porosity of silica bricks varies from ______________ percent?
A. 5 to 10
B. 20 to 30
C. 45 to 60
D. 60 to 75 - Ganister is a source of the ________________?
A. Silica
B. Periclase
C. Lime
D. None of these - Zirconia refractories are not used in_____________________?
A. Making sheaths for thermocouple
B. Lining high temperature ceramic kilns
C. Furnaces subjected to fluctuating temperature
D. High frequency induction furnaces in the form of inductors
