Carbothermal reduction of low-grade pyrolusite by microwave heating

Abstract

Pyrolusite was carbothermally reduced using coal by microwave heating, and the crystal structures and microstructures of the samples were characterized after microwave heating using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). When the reductants proportion was of 10 percent, the reduction temperature was of 800 °C and the holding time was of 40 minutes, the reduction ratio of MnO₂ to MnO was 97.2%, and Fe₂O₃ was almost completely transformed to Fe₃O₄ and there was no Fe(II) produced. Moreover, it was found that the low-grade pyrolusite was carbothermally reduced using microwave heating with lower temperature and shorter processing time. These results show that microwave heating can be applied effectively and efficiently to the carbothermal reduction processes of low-grade pyrolusite.