Solution:

Proximate analysis of concentrate is







Basis: 1000 kg of zinc concentrate
Roasting reactions ore



.

Weight of roasted ore =853.8 kg and
%Sin roasted ore =1.04% (a) Answer.

Combustion of coal







Theoretical volume if air for combustion + roasting as determined by the roasting and combustion equations is Ans. (b)

Flue gas consists of , , ,

Amount of ,  and  can be determined from the roasting and combustion equations.
Let x in kg moles of flue gas

in flue gas

Excess in flue gas

In flue gas is theoretical  theoretical air is determined in b. From theoretical air, theoretical can be determined



mols  Ans. (c)

Composition of flue gas










Excess air = 131.6% Ans. (c)