Sulfuric acid is the chemical produced in the United States withthe highest volume of production. In one of the earliest processesused to make it, an ore containing iron pyrites (FeS2) is roasted(burned) with air. The following reactions take place in theroasting furnace: The gas leaving the reactor goes to a catalyticconverter in which most of the SO2 produced is further oxidized toSO3: Finally, the gas leaving the converter passes through anabsorption tower, in which the SO3 is absorbed in water to producesulfuric acid (H2SO4). (a) An ore containing 82 wt% FeS2 and 18%inerts is fed to a roasting furnace. Dry air is fed to the furnacein 40% excess of the amount theoretically required to oxidize allof the sulfur in the ore to SO3, an FeS2 oxidation of 85% isobtained, with 40% of the FeS2 converted forming sulfur dioxide andthe rest forming sulfur trioxide. Two streams leave the roaster: agas stream containing SO2, SO3, 02, and N2, and a solid streamcontaining unconverted pyrites, ferric oxide, and inert material inthe ore. Calculate the required feed rate of air instandard cubic meters per 100 kg of ore roasted and the molarcomposition and volume (SCMJ100 kg of ore) of the gas leaving theroasting oven.
