Katri Piekkari, Katja Ohenoja, Visa Isteri, Pekka Tanskanen, Mirja Illikainen, Immobilization of heavy metals, selenate, and sulfate from a hazardous industrial side stream by using calcium sulfoaluminate-belite cement, Journal of Cleaner Production, Volume 258, 2020, 120560, ISSN 0959-6526, https://doi.org/10.1016/j.jclepro.2020.120560
Immobilization of heavy metals, selenate, and sulfate from a hazardous industrial side stream by using calcium sulfoaluminate-belite cement
|Author:||Piekkari, Katri1; Ohenoja, Katja1; Isteri, Visa2;|
1Fibre and Particle Engineering Research Unit, University of Oulu, Pentti Kaiteran katu 1, 90014, Oulu, Finland
2Process Metallurgy Research Unit, University of Oulu, Pentti Kaiteran katu 1, 90014, Oulu, Finland
|Online Access:||PDF Full Text (PDF, 2 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe202003107772
|Publish Date:|| 2020-03-10
Release of heavy metals from different industries and industrial waste is a major global threat for as well humans as ecosystems. In this study, immobilization of an industrial filter sludge (FS) with an extremely high content of several heavy metals (24.6 wt% Pb, 21.7 wt% Hg, and 9.00 wt% Se) and sulfate via calcium sulfoaluminate-belite (CSAB) cement was tested. The ratios of 25%, 50% and 75% of CSAB addition were tested, and the target was to achieve immobilization of the hazardous components. The leaching of Pb, Hg, SeO₄, SO₄, Ni, Cd, Cu, and As was monitored, and the structure of the immobilized materials was examined via X-ray powder diffraction (XRD) and field emission scanning electron microscopy-energy dispersive spectroscopy (FESEM-EDS) analysis. It was observed that Hg, Cu, As, Cd, and Ni were immobilized completely and leaching of Pb was reduced by 69% from the theoretical release. On the other hand, the leaching of SeO₄ and SO₄ experienced major increase when CSAB was added. XRD indicated significant ettringite formation as the amount of added CSAB increased, and the formation of gypsum as the amount was decreased. FESEM-EDS indicated that the immobilization was largely based on encapsulation into the CSAB binder, but chemical immobilization into the ettringite binder was also observed. It was concluded that the increased release of SO₄ and SeO₄ might have resulted from an excess amount of sulfates (added gypsum) during hydration.
Journal of cleaner production
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
218 Environmental engineering
216 Materials engineering
212 Civil and construction engineering
The work was conducted in the CECIRE project which was funded by Business Finland and the following companies: Boliden Harjavalta, Boliden Kokkola, Yara Suomi, Fortum Waste Solutions, and Outokumpu Stainless.
© 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).