washing action of metal.
corrosion by layer of slag.
both (a) & (b).
neither (a) nor (b).
✅ The correct answer is option A.
Refractory Technology MCQs
212. Presence of MgO in alumino-silicate refractories __________ its refractoriness.
increases
lowers
does not affect
either (a) or (b); depends on its quantity
✅ The correct answer is option B.
213. Pyrometric cone equivalent (PCE) value (Segar cone) of ‘superduty refractories’ is more than 33 which corresponds to a temperature of __________ °C.
1520
1630
1670
1730
✅ The correct answer is option D.
214. Firing temperature of magnesite bricks is about __________ °C.
800-1000
1000-1200
1600-1800
2400-2600
✅ The correct answer is option C.
215. Fusion point of a basic refractory material is
reduced by the addition of acid oxides.
increased by the addition of acid oxides.
not affected by the addition of acid oxides.
always less than 1000°C.
✅ The correct answer is option A.