University of Oulu

Katri Piekkari, Visa Isteri, Katja Ohenoja, Mirja Illikainen, Hazardous industrial filter sludge immobilization with mayenite and gypsum, Journal of Cleaner Production, Volume 387, 2023, 135873, ISSN 0959-6526,

Hazardous industrial filter sludge immobilization with mayenite and gypsum

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Author: Piekkari, Katri1; Isteri, Visa2; Ohenoja, Katja1;
Organizations: 1Fiber and Particle Engineering Research Unit, Faculty of Technology, PO Box 4300, 90014, University of Oulu, Finland
2Process Metallurgy Research Unit, Faculty of Technology, PO Box 4300, 90014, University of Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 5.8 MB)
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Language: English
Published: Elsevier, 2023
Publish Date: 2023-01-16


Heavy metals escaping from industrial processes and industrial waste are a significant environmental hazard all around the globe. Since they cannot be destroyed, the only way to manage the pollution is to capture and contain the hazardous components. This study focuses on stabilization-solidification of a highly toxic industrial filter slag that contains a range of different heavy metals in extremely high quantities. The stabilization-solidification treatment was executed with a mayenite and gypsum based solid cementitious binder. The major components that were monitored during the study were selenium, lead and sulphate. Different ratios of gypsum addition were tested in order to observe the effect of total sulphate content in the system to the immobilization efficiency of anionic selenium and sulphate. During the experiments, all cationic heavy metals were immobilized efficiently, most of them achieving the immobilization efficiencies of more than 99.9%. By adjusting the sulphate content of the system, the immobilization efficiency of selenium was improved from 95.669% to 99.925% and the immobilization efficiency of sulphate raised from 96.069% to above 99.964%. Controversially, the immobilization of lead was at its highest (99.999%) with high sulphate content and dropped to 98.162% as the sulphate rate decreased. The results show clearly that mayenite has good potential for stabilization-solidification applications.

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Series: Journal of cleaner production
ISSN: 0959-6526
ISSN-E: 1879-1786
ISSN-L: 0959-6526
Volume: 387
Pages: 1 - 9
Article number: 135873
DOI: 10.1016/j.jclepro.2023.135873
Type of Publication: A1 Journal article – refereed
Field of Science: 218 Environmental engineering
216 Materials engineering
222 Other engineering and technologies
Copyright information: © 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (