3203. Insulating refractories should have
high porosity
low thermal conductivity
both (a) and (b)
neither (a) not (b)
✅ The correct answer is option B.
3208. Mixing of ground refractory material and water is done in a __________ mill.
pug
ball
tube
rod
✅ The correct answer is option A.
3212. Bottom of basic open hearth furnace are constructed of
dead burnt magnesite ramming mass.
porous fireclay bricks.
semi-silica bricks.
silicon carbide bricks.
✅ The correct answer is option A.
3179. __________ of carbon blocks in the hearth of blast furnace helps in avoiding skull formation, when it becomes cold.
High thermal conductivity
Low porosity
Non-wetting characteristics
High density
✅ The correct answer is option C.
3182. RUL of refractories depends on the
chemical composition.
physical structure.
presence of impurities like iron & alkali.
all (a), (b) and (c).
✅ The correct answer is option D.
3189. Vacuum steel degassing units are lined with
silica bricks
low duty firebricks
high alumina bricks
graphite blocks
✅ The correct answer is option C.
3193. Silica bricks have low spalling resistance below 600°C, due to its
very high thermal conductivity.
high co-efficient of expansion upto this temperature.
high thermal diffusivity.
low refractoriness.
✅ The correct answer is option B.
3198. Most Cermets, which normally have high thermal conductivity and high thermal shock resistance, comprises of ceramic & metallic components of __________ percent respectively.
80 and 20
20 and 80
50 and 50
60 and 40
✅ The correct answer is option A.
3204. Which property is important for bricks used in the combustion chamber & dome of blast furnace stoves ?
High refractoriness.
High resistance to spalling.
High strength and density.
All (a), (b) and (c).
✅ The correct answer is option A.
3209. Zirconia refractory
does not react with basic slags.
is produced from baddeleyite.
can not be used as an insulator.
has poor electrical conductivity at high temperature.
✅ The correct answer is option B.