Question

The slurry, in its movement down the kiln, encounters a progressively higher temperature. At first, the water is driven off and ___  is liberated.

(a) SiO2

(b) CO2

(c) Gypsum

(d) CaO

I have been asked this question during an online interview.

This is a very interesting question from Wet Process in division Cement of Concrete Technology

Answer 1

Correct answer is (b) CO2

To explain I would say: At 900°C limestone decomposes, CaCO3.CaO + CO2 (endothermic reaction) CO2 is swept away by current air.