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Shunda Lin, Lei Gao, Yong Yang, Jin Chen, Shenghui Guo, Mamdouh Omran, Guo Chen, Dielectric properties and high temperature thermochemical properties of the pyrolusite-pyrite mixture during reduction roasting, Journal of Materials Research and Technology, Volume 9, Issue 6, 2020, Pages 13128-13136, ISSN 2238-7854,

Dielectric properties and high temperature thermochemical properties of the pyrolusite-pyrite mixture during reduction roasting

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Author: Lin, Shunda1; Gao, Lei2; Yang, Yong3;
Organizations: 1Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, PR China
2Key Laboratory of Green-Chemistry Materials in University of Yunnan Province, Yunnan Minzu University, Kunming 650500, PR China
3College of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 400044, PR China
4Process Metallurgy Research Group, Faculty of Technology, University of Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.8 MB)
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Language: English
Published: Elsevier, 2020
Publish Date: 2020-10-05


Manganese sulfate is widely used in electrolytic manganese production, catalysts, batteries, and other fields. However, the preparation of manganese sulfate from conventional roasting process of pyrolusite with additive of pyrite has disadvantages including long roasting time and low efficiency. Thus, microwave heating is used as an alternative for the preparation of manganese sulfate instead of traditional heating to destroy the dense structure of minerals and to further improve the heating efficiency which is dominating by dielectric properties of the material. Therefore, to evaluate the mechanism of preparation of manganese sulfate with microwave heating, experiments were carried out to explore the dielectric and thermochemical properties of pyrolusite-pyrite mixture at high temperature. The dielectric properties of pyrolusite-pyrite mixtures with different ratios were measured at high temperature using the resonant cavity perturbation technique, which has been widely used to study the dielectric properties of different metallurgical materials. It was found that with the increase of temperature, the microwave absorption properties of pure pyrolusite decreased from 28.173 F/M to 25.931 F/M. The wave-absorbing property of the soft pyrite/pyrite mixture increased to 41.218 F/M, indicating that pyrite can obviously improve the wave-absorbing property of the mixture. In addition, the characteristics of pyrolysis and reduction were studied systematically, and the pyrolysis and reduction process was divided into four stages according to the difference of temperature: 30 ℃-200 ℃, 200 ℃-400 ℃, 400 ℃-600 ℃, 600 ℃-900 ℃, corresponding to the separation of adsorbed water and bound water, MnO₂ decomposition, desulfurization redox reaction of FeS₂ and desulfurization redox reaction of Fe(1-x) S, respectively. This work highlights the possibility of reducing manganese ore by microwave heating with an additive of pyrite and finds that pyrite can modify the microwave absorption properties of pyrolusite.

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Series: Journal of materials research and technology
ISSN: 2238-7854
ISSN-E: 2214-0697
ISSN-L: 2238-7854
Volume: 9
Issue: 6
Pages: 13128 - 13136
DOI: 10.1016/j.jmrt.2020.09.056
Type of Publication: A1 Journal article – refereed
Field of Science: 218 Environmental engineering
Funding: The financial support by the National Natural Science Foundation of China (No: U1802255) and Innovative Research Team (in Science and Technology) in University of Yunnan Province were sincerely acknowledged.
Copyright information: © 2020 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (