Abstract:The extraction of manganese from a semi-oxidized manganese ore was investigated with sucrose as the reducing agent in dilute sulfuric acid medium. The kinetics of leaching manganese from the complex ore containing MnCO 3 and MnO 2 was also investigated. The effects of sucrose and sulfuric acid concentrations, leaching temperature and reaction time on the total Mn (TMn), MnO 2 and MnCO 3 leaching were investigated. Results showed that MnCO 3 could more easily react with hydrogen ions than MnO 2 in ores, and MnO 2 decomposition could be advantageous for MnCO 3 leaching. The leaching efficiencies of 91.8% for total Mn, 91.4% for MnO 2 and 96.9% for MnCO 3 were obtained under the following optimized conditions: 0.035 mol/L sucrose concentration, 5 mol/L sulfuric acid concentration, 60 min of reaction time and 363.2 K of leaching temperature. In addition, it was found that the leaching process of semi-oxidized manganese ore follows the shrinking core model and the leaching rate was controlled by chemical reaction and diffusion. The apparent activation energy of the total manganese, MnO 2 , and MnCO 3 leaching were 40.83, 40.59, and 53.33 kJ·mol −1 , respectively.