Effect of microwave heating on the microstructures and kinetics of carbothermal reduction of pyrolusite ore

Qianxu Ye, Jin Chen, Guo Chen, Jinhui Peng, C. Srinivasakannan, Rongsheng Ruan

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

This article focuses on the development of phase transformation and morphology of low-grade pyrolusite during carbothermal reduction using microwave heating. The XRD, SEM and EDS results show that selective carbothermal reduction of MnxOy and FexOy in pyrolusite is easy to realize with microwave heating, which can reduce MnO2 to MnO, and Fe2O3 to Fe3O4, rather than FeO. It was also observed that the phases of Mn2O3, Mn3O4 and MnO appear at 300 °C, 450 °C and 500 °C, respectively. The MnO phase, formed by the accumulation of MnO sphere particle with a diameter of 266.75–420.05 nm, is loose and porous. At a temperature of 750 °C, the Mn2SiO4 layer of about 316 nm in thickness, tightly wrapping SiO2 particle is generated at the interface between MnO and SiO2 embedded with MnO. Above 650 °C, Fe2O3 in pyrolusite can be transformed into a very dense Fe3O4 phase.

Original languageEnglish (US)
Pages (from-to)1871-1878
Number of pages8
JournalAdvanced Powder Technology
Volume29
Issue number8
DOIs
StatePublished - Aug 2018

Bibliographical note

Funding Information:
Financial supports from the Key Projects in the National Science & Technology Pillar Program during the Twelfth Five-year Plan Period (No.: 2015BAB17B00 ), Specialized Research Fund for the Doctoral Program of Higher Education (No.: 20125314120014 ) and the Applied Foundation Fund of Yunnan Province of China (No.: 2012FD015 ), and the Hunan Provincial Science and Technology Plan Project , China (No. 2016TP1007 ) were sincerely acknowledged.

Publisher Copyright:
© 2018 The Society of Powder Technology Japan

Keywords

  • Carbothermal reduction
  • Microwave heating
  • Phase transformation
  • Pyrolusite

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