Sulfation of inorganic chlorides (KCl, CaCl2 and NaCl) of mean particles size 75-125 mum was done in a lab-scale tubular reactor. The reactor was supplied with a mixed gas consisting Of SO2:0.3-1.3vol%, O-2:2.5-15vol% and H2O:5-20vol% in the temperature range 623-1123 K. The rates of HCl emission from the particles samples were measured and compared. It was found that at 1023 K, an HCl of about 8000ppm was emitted from CaCl2 and this emission concentration was more than 3 times as high as those from NaCl and KCl. The reaction kinetic parameters such as rate constants and reaction orders with respect to SO2, O-2 and H2O partial pressures were determined for the sulfation of NaCl, KCI and CaCl2. The rate of HCl emission from KCI, CaCl2 and NaCl became increasingly high when the temperature was raised above 923 K and depend on SO2, O-2, and H2O partial pressures. It was considered that an increase in the rate of HCl emission from the inorganic chlorides at temperatures above 923 K was caused by a change in the reaction mode from a gas-solid to a gas-liquid and/or a gas phase reaction, owing to a partial melting and/or volatilization of the inorganic chlorides. (C) 2004 Elsevier Ltd. All rights reserved.