Manganese leaching during high concentration flue gas desulfurization process with semi-oxidized manganese ore was studied in this paper. It was found that there were different reaction pathways among which MnO2, Mn2O3 and MnCO3 in semi-oxidized manganese ore during flue gas desulphurization and manganese leaching. High SO2 concentration facilitated redox reaction between MnO2 and SO2, and high concentration of H2SO4 accelerated MnCO3/Mn2O3 leaching from semi-oxidized ore. Kinetics study showed that manganese leaching in flue gas desulfurization process with semi-oxidized ore was controlled by a mixed-control model, that is the surface chemical reaction and mass diffusion dominated both the oxidation of SO2 and manganese leaching process. The apparent activation energy was 13.05 kJ.mol(-1) and the reaction orders with respect to SO2 and H2SO4 concentration were 1.38 and 0.10, respectively. Finally, a semi-empirical rate equation based on shrinking core model was derived to describe the process. (C) 2019 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.