The kinetics of chlorination and carbochlorination of PbSO4 with Cl-2 + N-2 and Cl-2 + CO + N-2 gas mixtures has been studied using thermogravimetric measurements in the range 700-900 degrees C. The chlorination reaction rate of PbSO4 with Cl-2 + N-2 increases with rise in the chlorine content in the gas mixture. The reaction order is about 0.66 with respect to chlorine. The chlorination rate of PbSO4 is controlled by a chemical reaction mechanism with an apparent activation energy of about 174 kJ/mol. In the same temperature range, the apparent activation energy of the carbochlorination of lead sulfate by Cl-2 + CO + N-2 gas mixture is about 114 kJ/mol. The reaction order is about 0.72 with respect to Cl-2 + CO. The maximum reaction rate is obtained by using a carbochlorinating gas mixture having a Cl-2/(Cl-2 + CO) ratio equal to about 0.6.