Problem 1: Material balance in roasting of zinc concentrate


Zinc concentrates of a location are composed of 60% zinc, present as , iron present as and . On roasting Zn oxidizes to , iron to  and S to of  however, remains unchanged. Coal equal to of raw one is used: the ashes from the coal do not mix with the ore, but the products of combustion pass through the furnace and into the flue mixed with the gases from the roasting. The coal is .

The flue gases carry oxygen.

Calculate:

a) The weight of roasted ore, and the % as sulphur in the roasted ore.

b) The theoretical vol. of air used in roasting and for combustion of coal.

c)The % composition of the flue gases and the % excess air used above the theoretical requirement for roasting and combustion