3213. Which is a neutral refractory ?
Graphite
Magnesite chrome
Silica
Magnesia
✅ The correct answer is option A.
3180. Chromite refractories are used in
bottom of soaking pits.
between acid & basic linings in basic open hearth furnaces to prevent their chemical action with each other.
both (a) & (b)
neither (a) and (b)
✅ The correct answer is option C.
3183. Sillimanite is a __________ refractory.
basic
neutral
high alumina
insulating
✅ The correct answer is option C.
3190. Grog addition in fireclay during brick manufacture is done to
reduce its shrinkage on heating.
impart greater spalling resistance.
enhance the strength of fired refractories.
all (a), (b) and (c).
✅ The correct answer is option D.
3194. Fireclay refractories have
low co-efficient of thermal expansion.
poor thermal spalling resistance.
tendency to expand unduly high during firing.
very high cost.
✅ The correct answer is option A.
3199. High thermal conductivity of a refractory material is not important, when it is to be used in the
coke oven regenarators
muffle furnace
blast furnace
recuperators
✅ The correct answer is option C.
3201. Maximum apparent porosity of magnesite bricks is about __________ percent.
8
24
44
58
✅ The correct answer is option B.
3206. __________ bricks should not be used in oxidising atmosphere.
Tar dolomite
Carbon
Silica
Fireclay
✅ The correct answer is option B.
3211. Grog
contains both alumina and silica.
iscrushed firebrick.
is a non-plastic material.
all (a), (b) and (c).
✅ The correct answer is option D.
3216. Silicon carbide refractories are used in the
muffle furnace
zinc smelting furnace
ceramic recuperators
all (a), (b) and (c)
✅ The correct answer is option D.