Manganese Ore Decomposition and Carbon Reduction in Steelmaking

Abstract To improve the direct alloying of manganese ore in steelmaking, the decomposition and carbon reduction of manganese ore was studied using a differential thermal analyzer and resistance furnace. The remaining material after manganese ore decomposition at 1,600 °C was a mixture of 43 % MnO, 40 % MnSiO ₃ and FeO, and 17 % MnSiO ₃ . The remaining material after the carbon reduction of the manganese ore was a mixture of metal (30.8 % Mn ₇ C ₃ and 16.1 % FeC ₃ ) and slag (2.5 % FeO, 5.1 % SiO ₂ , and 18.8 % MnO). The high-temperature (1,200 ℃) decomposition and reduction of manganese ore produce manganese carbonate, manganese dioxide, and manganese salicylate sesquioxide. However, because it is not easy to decompose the manganese silicate in the manganese ore, the proportion of ore being reduced by carbon is small. Therefore, the increase of the manganese reduction of manganese silicate is critical to the direct alloying of manganese ore. Adding calcium oxide or magnesium oxide to the manganese ore improves the reduction of manganese ore, whereas adding slag from the initial stage or endpoint of the converter process has little effect on the manganese ore reduction.