REACTIVITY OF DIFFERENT TYPES OF LIMESTONE SUITABLE FOR DESULPHURISATION

Wet flue gas desulphurisation (FGD) process with ground limestone is the most frequently used technology for the Flue Gas Desulphurisation (FGD) process. This contribution is devoted to the testing of the reactivity of CaCO3 prepared from FGD gypsum (FGDG) by the reaction with ammonium sulphate. The reactivity of limestone was evaluated on the basis of the rate of the reaction between 1 M HCl added to the water suspension of precipitated and/or ground limestone, keeping pH at constant value - approximately 4. It was found that the reactivity of limestone prepared from FGDG is lower in the beginning of the reaction in comparison with ground limestone mineral. However, in the whole reaction range, all studied limestone samples showed approximately the same reactivity. The obtained results suggest that CaCO3 prepared from FGDG is a suitable material for the desulphurisation process. Consequently, demands for the fresh ground limestone may be minimised. Ammonium sulphate as a side product from the conversion of FGDG is a valuable fertilizing component.