Thermal analysis and kinetic modeling of manganese oxide ore reduction using biomass straw as reductant

In this study biomass straw was used as a reductant and fuel for the reduction of manganese oxide ore at low temperature of up to 600 °C. XRD analysis of original and roasted ore was made to identify the reduction mechanism. The reduced products changed with the different amount of straw, and the manganese oxide ore was successfully reduced to acid-soluble MnO with over 30% biomass straw. Several mixtures with different weight ratios of biomass straw and ore were subjected to thermal analysis, showing that reduction reaction commenced at approximately 310 °C and was almost completed at 600 °C. Thermal analysis data further confirmed the individual thermal reaction regions associated with developments of individual manganese phases during the heating and were used to calculate the corresponding kinetics of the biomass reduction process. The activation energy (E) was calculated to be 470 kJ/mol at 300–390 °C, 510 kJ/mol at 400–480 °C, and 430 kJ/mol at 490–640 °C respectively.