University of Oulu

Shunda Lin, Kangqiang Li, Yong Yang, Lei Gao, Mamdouh Omran, Shenghui Guo, Jin Chen, Guo Chen, Microwave-assisted method investigation for the selective and enhanced leaching of manganese from low-grade pyrolusite using pyrite as the reducing agent, Chemical Engineering and Processing - Process Intensification, Volume 159, 2021, 108209, ISSN 0255-2701,

Microwave-assisted method investigation for the selective and enhanced leaching of manganese from low-grade pyrolusite using pyrite as the reducing agent

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Author: Lin, Shunda1; Li, Kangqiang1; Yang, Yong2;
Organizations: 1Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, PR China
2College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, PR China
3Kunming Key Laboratory of Energy Materials Chemistry, Key Laboratory of Green-Chemistry Materials in University of Yunnan Province, Yunnan Minzu University, Kunming 650500, PR China
4Process Metallurgy Research Group, Faculty of Technology, University of Oulu, Finland
5Kunming University of Science and Technology, Kunming, China
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 2.4 MB)
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Language: English
Published: Elsevier, 2021
Publish Date: 2022-11-02


The recovery mechanism of manganese from low-grade pyrolusite was studied through microwave and conventional leaching, respectively, and pyrite was used as the reducing agent. An improvement on the manganese leaching rate with microwave heating was noticed which may be caused by the suppressing of the formation of sulfur passivation layer by the unique dipole rotation heating mechanism of microwave energy. To confirm this hypothesis, the leaching time, the amount of reducing agent, and the concentration of sulfuric acid were studied, and the surface compositions of the leaching residues were analyzed. The results evidenced that the sulfur content on the surface of residue produced by microwave leaching was significantly reduced compared to the results produced by conventional heating, which proved the rationality of the hypothesis. The recovery of leaching assisted with microwave heating was improved compared to that assisted with conventional heating under the same experimental conditions (liquid-solid ratio: 10:1, leaching temperature: 90 ℃, M(pyrite)/M(pyrolusite): 0.2, sulfuric acid concentration: 1.2 mol/L, stirring speed: 400 rpm). The corresponding peak value of the leaching rate was 95.07 % and 75.08 %. Additionally, microwave leaching is very environmentally friendly since it significantly reduces the amount of reducing agent and sulfuric acid as well as reaction time.

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Series: Chemical engineering and processing
ISSN: 0255-2701
ISSN-E: 1873-3204
ISSN-L: 0255-2701
Volume: 159
Article number: 108209
DOI: 10.1016/j.cep.2020.108209
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Funding: Financial supports from the National Natural Science Foundation of China (No: U1802255), the Key Projects in the National Science & Technology Pillar Program during the Twelfth Five-year Plan Period (No. 2015BAB17B00), the Hunan Provincial Science and Technology Plan Project, China (No. 2016TP1007), and Innovative Research Team (in Science and Technology) in University of Yunnan Province were sincerely acknowledged.
Copyright information: © 2021. This manuscript version is made available under the CC-BY-NC-ND 4.0 license by