A. Are stored under controlled temperature & humidity to avoid hydration
B. Are used in outer lining of L.D. converters
C. Have poorer hydration resistance than pitch bonded bricks
D. All A., B. and C.
Related Mcqs:
- Tar dolomite bricks are used in the_________________?
A. Basic Bessemer converter
B. Basic open hearth furnace
C. Electric furnaces
D. All A., B. and C. - Dolomite bricks have good resistance to attack by_____________________?
A. Molten steel
B. Iron oxide
C. Lime slag
D. None of these - Pure oxide refractories are generally monocrystalline in nature and are self bonded _______________ bricks are generally used as moderator in nuclear reactors?
A. Beryllia
B. Carborundum
C. Corundum
D. Thoria - Lower part of hot metal mixer are lined with _____________ bricks?
A. Superduty fireclay
B. High alumina
C. Silica
D. Carborundum - RUL of refractories depends on the _____________________?
A. Chemical composition
B. Physical structure
C. Presence of impurities like iron & alkali
D. All A., B. and C. - With increase in the alumina content in firebricks, its fusion point (refractoriness) ?
A. Decreases linearly
B. Remains unchanged
C. Increases
D. Decreases - 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 - Pick out the wrong statement ?
A. Electrical conductivity of refractory is not important, when these are to be used in electrical
furnaces
B. Graphite and metals are the good electrical conductor among the refractories and others are all
electrical insulators
C. Refractories used for lining electrical furnaces should ordinarily have very low electrical
conductivity
D. Electrical conductivity of porous refractory material is low - Cold crushing strength of ordinary fireclay brick is about 950 kg/cm2. On exposure to a temperature of about 1500°C, its crushing strength may come down to as low as ______________ kg/cm2?
A. 450
B. 250
C. 150
D. 65 - Refractory bricks with lower permeability is produced by using __________________?
A. Higher firing temperature
B. Higher moulding pressure
C. Finer grog size
D. All A., B. and C.
