University of Oulu

Shunda Lin, Lei Gao, Yong Yang, Jin Chen, Shenghui Guo, Mamdouh Omran, Guo Chen, Efficiency and sustainable leaching process of manganese from pyrolusite-pyrite mixture in sulfuric acid systems enhanced by microwave heating, Hydrometallurgy, Volume 198, 2020, 105519, ISSN 0304-386X,

Efficiency and sustainable leaching process of manganese from pyrolusite-pyrite mixture in sulfuric acid systems enhanced by microwave heating

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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
2School of Chemistry and Environment, Yunnan Minzu University, Kunming 650500, PR China
3College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, PR China
4Kunming University of Science and Technology, Kunming, China
5Process Metallurgy Research Group, Faculty of Technology, University of Oulu, Finland
Format: article
Version: accepted version
Access: embargoed
Persistent link:
Language: English
Published: Elsevier, 2020
Publish Date: 2022-11-05


Recently, with the decrease in the quality of manganese resources, the efficient use of low-quality manganese ore resources has attracted widespread attention. At present, pyrite is often used as reducing agent to recover Mn(IV) in industrialization. However, the passivation of pyrite in the leaching reaction process will lead to a decreased reaction efficiency. Hence, in this study, microwave heating was applied in the reduction system in order to remove the inhibition of the passivation layer and accelerate the dissolution of pyrite, indicating an improvement in the corresponding Mn(IV) reduction efficiency. The results show that the leaching rate assisted by microwave heating was 95.07%, approximately 20% higher than that of conventional heating (75.08%), and the amount of sulfuric acid and pyrite was reduced by 14% and 20%, respectively. XPS analysis shows that there was an obvious sulfur elemental peak at 164.3 eV under traditional heating conditions, but it was absent when microwave heating was applied, and the elemental sulfur under conventional heating is 11.63%, which is higher than that under microwave heating (4.80%). Through scanning electron microscopy, it was noted that there are a large number of voids on the mineral surface under microwave heating, which can increase the solid-liquid contact area, effectively reducing the formation of the sulfur passivation layer and accelerating the dissolution of Mn (IV). In addition, the measurement of the dielectric constant of the solution mixture shows that the dielectric constant of the solution with mineral addition was increased from 36.533 (F/M) to 37.717 (F/M) and the loss tangent angle was increased from 8.61 × 10⁻³ to 9.21 × 10⁻³. It can be inferred that microwaves act directly on the mineral itself through the solution. Thus, the application of pyrite and microwave heating in the recovery of Mn(IV) is expected to effectively reduce the use of sulfuric acid, and achieve green, environmentally friendly and efficient leaching of manganese.

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Series: Hydrometallurgy
ISSN: 0304-386X
ISSN-E: 1879-1158
ISSN-L: 0304-386X
Volume: 198
Article number: 105519
DOI: 10.1016/j.hydromet.2020.105519
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 (Nos: U1802255, 51664035) and Innovative Research Team (in Science and Technology) at the University of Yunnan Province are sincerely acknowledged.
Copyright information: © 2020. This manuscript version is made available under the CC-BY-NC-ND 4.0 license by