3 H2SO4(acq,conc) + Fe2O3 -> Fe2(SO4)3 (300 °C)
Fe2(SO4)3 -> Fe2O3 + x SO2 + ySO3 + y/2 O2 (650 °C, where x+y=3)
In comparison with direct sulphuric acid decomposition the maximum temperature is lowered, there is no more need for catalysts and the material costs for the reactor is drastically reduced. One disadvantage is the increase of energy demand.
Experimental and theoretical modeling results are presented and discussed.