The chemical reaction between sulphur dioxide and calcined limestone and dolomite particles was investigated using a thermogravimetric analyser. The samples used in this study originated from different parts of Turkey. Sulphation reactions were conducted under isothermal conditions in a gaseous mixture consisting of 15 vol% CO2, 0.35 vol% SO2 and a balance of dry air by volume. Before sulphation all samples were completely calcined in a gaseous atmosphere of 15 vol% CO2 and 85 vol% dry air. It was observed that the sulphation reactions of samples are very rapid in their initial stage but after some reaction time, which varies depending on sample properties and temperature, the reaction rates quickly slow down. Also, the conversion-time results of sulphation experiments showed variations depending on the sulphation temperature, sorbent type and the physical properties of calcines.