Question

The processes of Calcination and roasting in metallurgical industries, respectively, can lead to

• A. Global warming and photochemical smog
• B. Photochemical smog and ozone layer depletion
• C. Photochemical smog and global warming
• D. Global warming and acid rain

Answer 1

The correct option is D Global warming and acid rain

Calcination: Heating of concentrated ore in the absence (or limited supply of air). Mainly used for carbonate ores.

$\text{Metal carbonate}\stackrel{\Delta }{⟶}\text{metal oxide}+C{O}_2\text{(causes Global warming)}$

Roasting : Heating of concentration ore in a regular supply of air. Mainly used for sulphide ores.

$\text{Metal sulphide}+O_2⟶\text{Metal oxide}+S{O}_2\text{(causes acid rain)}$