Cite this article as: |
Ruofeng Wang, Peng Gao, Shuai Yuan, Yanjun Li, Yingzhi Liu, and Cheng Huang, Fundamental investigation on the precise regulation of pyrolusite ore phase transformation, Int. J. Miner. Metall. Mater.,(2023). https://doi.org/10.1007/s12613-023-2688-4 |
To achieve the rational utilization of low-grade co-associated complex manganese ore resources, this paper systematically elucidated the mechanism of the phase transformation process of roasting in a reducing atmosphere with pyrolusite ore (MnO2) as the research object. According to the single-factor experiment results, the divalent manganese (Mn2+) reduction rate of the roasted product obtained as 95.30% at a roasting time of 25 min, a roasting temperature of 700°C, a CO concentration of 20at% and a total gas volume of 500 mL·min-1, in which the manganese was mainly in the form of manganosite (MnO). Scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) demonstrated the microstructural evolution of the roasted products, and the reduction of pyrolusite ore was completed gradually from the surface to the core. Thermodynamic calculations, X-ray photoelectron spectroscopy(XPS), and X-ray diffractometry (XRD) elucidated that the phase transformation of pyrolusite follows MnO2→Mn2O3→Mn3O4→MnO phase by phase and that the reduction of manganese oxides in each valence state proceeds simultaneously.