The gases from pyrite burning are fed to a Glover Tower where a fraction of the SO2 is transformed into H2SO4. Together with the gas, a stream consisting of 592 kg (77% H2SO4, 22% H2O, and 1% N2O3) comes from a Gay-Lussac Tower, and another one from lead chambers (178 kg of H2SO4, 64%); we feed 1.32 kg of HNO3 as catalyst makeup. From the tower we obtain 770 kg of acid (78%); see Fig.