University of Oulu

RSC Adv., 2020, 10, 23959.

Microwave catalyzed carbothermic reduction of zinc oxide and zinc ferrite : effect of microwave energy on the reaction activation energy

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Author: Omran, Mamdouh1,2; Fabritius, Timo1; Heikkinen, Eetu-Pekka1;
Organizations: 1Process Metallurgy Research Group, Faculty of Technology, University of Oulu, Oulu, Finland
2State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, Shanghai University, Shanghai, China
3Kunming Key Laboratory of Energy Materials Chemistry, Yunnan Minzu University, Kunming, China
4Material Science and Engineering Dep., Carnegie Mellon University, Pittsburgh, USA
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.4 MB)
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Language: English
Published: Royal Society of Chemistry, 2020
Publish Date: 2020-07-01


Recently, more attention has been paid to the use of microwave (MW) energy in accelerating chemical reactions. The effect of microwave energy on the reduction of zinc oxide and zinc ferrite was investigated. The results indicated that the temperatures required to initiate zinc oxide and zinc ferrite reduction under MW heating were 550 and 450 °C, respectively, while under conventional thermal (CT) heating, were 950 and 850 °C, respectively. Apparently, the MW reaction had a negative standard Gibbs free energy (ΔG) at a lower temperature (∼400 °C) when compared to the CT reaction. Additionally, the activation energy (Ea) substantially decreased from 223.7 and 221.1 kJ mol−1 under CT heating to 64.8 and 32.9 kJ mol−1 under MW heating for Zn oxide and zinc ferrite, respectively. The enhancement in zinc reduction under MW energy was due to the rapid and bulk heating phenomena of MWs as well as the interactions occurring between the electromagnetic MW pattern and the molecules of heated materials.

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Series: RSC advances
ISSN: 2046-2069
ISSN-E: 2046-2069
ISSN-L: 2046-2069
Volume: 10
Issue: 40
Pages: 23959 - 23968
DOI: 10.1039/D0RA04574H
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Funding: This work was funded by Business Finland (SYMMET research program).
Copyright information: This journal is © The Royal Society of Chemistry 2019. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.