3353. Ceramic recuperators used for waste heat recovery from high temperature flue gas going out of the furnace is made of
fireclay
silicon carbide
corrundum
siliceous fireclay
✅ The correct answer is option B.
3358. Which is the stable form of silica between 1470°C and the melting point 1713°C ?
Cristobalite
Tridymite
Quartz
None of these
✅ The correct answer is option A.
3363. Carbon refractory blocks
are wetted by molten iron.
are used in the hearth of blast furnace.
are acidic in nature.
all (a), (b) and (c).
✅ The correct answer is option B.
3368. Refractoriness/fusion points of ‘superduty’ refractories is __________ °C.
1520-1630
1630-1670
> 1730
> 2000
✅ The correct answer is option C.
3335. ‘Super refractories’ are made from pure
carbides
oxides
borides
nitrides
✅ The correct answer is option B.
3341. Lower part of hot metal mixer are lined with __________ bricks.
superduty fireclay
high alumina
silica
carborundum
✅ The correct answer is option D.
3345. Carbon refractories have very high
wetting characteristics
refractoriness
thermal conductivity
both (b) and (c)
✅ The correct answer is option D.
3348. Tar bonded dolomite bricks
are stored under controlled temperature & humidity to avoid hydration.
are used in outer lining of L.D. converters.
have poorer hydration resistance than pitch bonded bricks.
all (a), (b) and (c)
✅ The correct answer is option D.
3354. Highest melting (m.p = 3070°C) oxide refractory is
alumina
thoria
zirconia
magnesia
✅ The correct answer is option B.
3359. Ferromagnetic ceramic material is not used in the
thermal insulation
transformers
magnetic switches
television sets
✅ The correct answer is option A.