3343. __________ bricks are used in the burning zone of a cement rotary kiln.
High alumina
Fireclay
Thoria
Silicon carbide
✅ The correct answer is option A.
3347. Bauxite calcining rotary kilns are lined with __________ bricks.
fireclay
carbon
85% alumina
corundum
✅ The correct answer is option C.
3352. Fireclay bricks are not used in the
beehive coke oven.
by-product coke oven walls.
combustion chamber of B.F. stoves.
coke oven regenerators.
✅ The correct answer is option B.
3357. Which of the following is not an acidic refractory ?
Silica bricks
Fireclay bricks
Bauxite bricks
Magnesia bricks
✅ The correct answer is option D.
3362. Maximum alumina content in high alumina refractory can be as high as __________ percent.
30
50
70
90
✅ The correct answer is option D.
3367. Graphite or carbon refractories
exihibit wetting characteristics.
should be used in neutral or reducing atmosphere.
exhibit high shrinkage on thermal treatment.
are not resistant to corrosion by slag.
✅ The correct answer is option B.
3334. Cermets are
composite material containing both ceramic & metallic constituents.
having high strength & resistance to high temperature.
used in space vehicles, missiles & nuclear energy plants.
all (a), (b) and (c).
✅ The correct answer is option D.
3340. Which is not an alumino-silicate refractory?
Fireclay bricks.
Mullite bricks.
Tar dolomite bricks.
High alumina bricks.
✅ The correct answer is option C.
3344. Si percentage in silica refractories used in the walls of coke oven is about
45
60
80
95
✅ The correct answer is option D.
3349. Natural silica
mainly contains quartz.
is not stable at high temperature.
transforms to other allotropic forms i.e tridymite and cristoballite involving very high volume changes.
all (a), (b) and (c).
✅ The correct answer is option D.