KINETIC AND QUANTITATIVE STUDIES OF THE FORMATION OF SO2 FROM IRON(II) AND CALCIUM SULFATES BY SEQUENTIAL AND FRACTIONATED PYROLYSIS

The formation rates of sulfur dioxide were studied when iron and calci um sulfates were pyrolyzed sequentially at different temperatures in o rder to calculate the activation energies and frequency factors. These will be used to provide qualitative information concerning the format ion of SO2 when different coals are pyrolyzed. It is possible to calcu late the pyrolysis temperature needed to degrade the salts totally in a fixed time. In practice the temperature had to be higher to obtain c lose to 100% conversion, probably due to effects from the platinum fil ament. The activation energies and frequency factors were 220 +/- 5 kJ mol(-1) and 10(12) s(-1) for FeSO4 . 7H(2)O and 205 +/- 5 kJ mol(-1) and 10(7) s(-1) for CaSO4 . 2H(2)O. The yield of sulfur dioxide at dif ferent temperatures and the influence of sample size were also studied . Fractionated pyrolyses were carried out in order to quantify the two sulfates in a blend.