University of Oulu

Piekkari, K., Isteri, V., Ohenoja, K., Illikainen, M. (2021) Effect of Gypsum Content on CSAB Cement-Based Immobilization of Se and SO 4 from Industrial Filter Sludge and Sodium–Selenium Salts. Journal of Hazardous, Toxic, and Radioactive Waste, 25 (3), 04021018. https://doi.org/10.1061/(ASCE)HZ.2153-5515.0000623

Effect of gypsum content on CSAB cement-based immobilization of Se and SO₄ from industrial filter sludge and sodium–selenium salts

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Author: Piekkari, Katri1; Isteri, Visa2; Ohenoja, Katja1;
Organizations: 1Fiber and Particle Engineering Research Unit, Faculty of Technology, Univ. of Oulu, PO Box 4300, 90014 Oulu, Finland
2Process Metallurgy Research Unit, Faculty of Technology, Univ. of Oulu, PO Box 4300, 90014 Oulu, Finland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 0.3 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe2021043028084
Language: English
Published: American Society of Civil Engineers, 2021
Publish Date: 2021-04-30
Description:

Abstract

Release of different heavy metals from various industries is a significant environmental hazard worldwide. In order to reduce the threat from these chemicals, different treatment methods are needed to make them harmless. This study approaches the problem by examining the effect of gypsum content for immobilization of selenium oxyanions selenite and selenate, and sulfate, with calcium sulfoaluminate belite (CSAB) cement-based ettringite binder systems. The study has two experimental sections. In the first section, an industrial filter sludge with high concentrations of selenium and sulfate is immobilized with CSAB and varying amounts of gypsum. The immobilization is efficient and reducing the gypsum amount in the hydrating mixture enhances the incorporation of both selenium and sulfate. The binding occurs through encapsulation and incorporation into ettringite and other hydrated phases. In the second section, two reagent grade sodium–selenium salts, sodium selenite and sodium selenate, are mixed with CSAB and varying amounts of gypsum. The immobilization is not effective and ettringite is not formed in large quantities, most likely due to high sodium content in the reacting system.

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Series: Journal of hazardous, toxic and radioactive waste
ISSN: 2153-5493
ISSN-E: 2153-5515
ISSN-L: 2153-5493
Volume: 25
Issue: 3
Article number: 04021018
DOI: 10.1061/(ASCE)HZ.2153-5515.0000623
OADOI: https://oadoi.org/10.1061/(ASCE)HZ.2153-5515.0000623
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
218 Environmental engineering
Subjects:
Dataset Reference: All data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
Copyright information: © 2021 American Society of Civil Engineers. The final authenticated version is available online at https://doi.org/10.1061/(ASCE)HZ.2153-5515.0000623.