The formation of HCl by sulfation of NaCl under municipal waste combustion conditions was studied experimentally. NaCl sulfation was carried out with a packed bed of NaCl reagent in the temperature range 623-1123 K. The amount of HCl formed from NaCl was found to increase with the increment of the concentrations Of SO2, O-2 and H2O. However, the dependence of HCl formation rate on the SO2, and H2O concentrations differed at temperatures above and below 923K. It was assumed that sulfation of NaCl proceeded by different reaction mechanisms in each temperature range. The existence of different reaction mechanisms at dofferent temperatures is responsible for the partial melting of NaCl solid at temperatures over 920 K. The equation of reaction rate of NaCl sulfation in the temperature range 623 -1123 K was formulated as follows. [GRAPHICS]