University of Oulu

Kangqiang Li, Qi Jiang, Lei Gao, Jin Chen, Jinhui Peng, Sivasankar Koppala, Mamdouh Omran, Guo Chen, Investigations on the microwave absorption properties and thermal behavior of vanadium slag: Improvement in microwave oxidation roasting for recycling vanadium and chromium, Journal of Hazardous Materials, Volume 395, 2020, 122698, ISSN 0304-3894, https://doi.org/10.1016/j.jhazmat.2020.122698

Investigations on the microwave absorption properties and thermal behavior of vanadium slag : improvement in microwave oxidation roasting for recycling vanadium and chromium

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Author: Li, Kangqiang1; Jiang, Qi1; Gao, Lei2;
Organizations: 1Key Laboratory of Unconventional Metallurgy, Ministry of Education, Kunming University of Science and Technology, Kunming 650093, PR China
2Key Laboratory of Green-Chemistry Materials in University of Yunnan Province, Kunming Key Laboratory of Energy Materials Chemistry, Yunnan Minzu University, Kunming 650500, PR China
3Panjin Institute of Industrial Technology, Dalian University of Technology, Panjin 124221, Liaoning, PR China
4Process Metallurgy Research Group, Faculty of Technology, University of Oulu, Finland
Format: article
Version: accepted version
Access: embargoed
Persistent link: http://urn.fi/urn:nbn:fi-fe2020042019372
Language: English
Published: Elsevier, 2020
Publish Date: 2022-04-14
Description:

Abstract

Vanadium slag contains high contents of vanadium and chromium with complex and dense structures, hence microwave heating instead of conventional methods is expected to destroy the dense structure and further to improve the extraction rate of vanadium and chromium, and exploring its dielectric properties is the prerequisite work. Microwave absorption properties and thermal behavior of vanadium slag were investigated. Results indicated that vanadium slag endowed excellent microwave absorption properties, with minimum εr′ value of 34.447 (F/M). Dielectric properties of vanadium slag varied with temperature, which changing trend was matched to the three stages of microwave heating characteristics identified by heating rates. Meanwhile, the changing process of dielectric properties also corresponded to the three processes of thermogravimetric characteristics: dehydration stage (30 °C-280 °C), oxidation decomposition of olivine phase and normal spinel phase (280 °C-650 °C), and oxidation decomposition of vanadium chromium spinel (650 °C-950 °C). Moreover, the maximum dielectric constant and highest microwave heating rate of vanadium slag both appeared at the temperature regime of 500 °C-550 °C, which was also the main temperature regime for oxidation decomposition of olivine phase and normal spinel phase in vanadium slag, demonstrating the appropriate process temperature for microwave heating technology to recycle vanadium slag.

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Series: Journal of hazardous materials
ISSN: 0304-3894
ISSN-E: 1873-3336
ISSN-L: 0304-3894
Volume: 395
Article number: 122698
DOI: 10.1016/j.jhazmat.2020.122698
OADOI: https://oadoi.org/10.1016/j.jhazmat.2020.122698
Type of Publication: A1 Journal article – refereed
Field of Science: 218 Environmental engineering
Subjects:
Funding: The authors acknowledge the financial supports from the National Natural Science Foundation of China (No: U1802255, 51504110 and 51424114) and Innovative Research Team (in Science and Technology) in University of Yunnan Province were sincerely acknowledged.
Copyright information: © 2020. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/.
  https://creativecommons.org/licenses/by-nc-nd/4.0/