Question

For how long must coke be burnt?

(a) 2-3 hours

(b) 6-8 hours

(c) 18-24 hours

(d) 30-36 hours

I had been asked this question in an online interview.

The origin of the question is Cements, Metallurgical Coke and Synthetic Resins topic in section Miscellaneous Materials of Engineering Material & Metallurgy

Answer 1

Correct option is (d) 30-36 hours

The best explanation: Coal is subjected to destructive distillation at a temperature of 1150-1200oC.This forms hard and porous coke which has high carbon content. The burning of this coke lasts for 18-24 hours but is about 25% longer for foundry coke.