Gas Evolution and Stability of Alkali-Activated MSWI Slag and Fly Ash: Implications for Safe Use and Energy Valorization

Beata Łaźniewska-Piekarczyk (), Grzegorz Dzido, Monika Czop and Małgorzata Kajda-Szcześniak
Additional contact information
Beata Łaźniewska-Piekarczyk: Faculty of Civil Engineering, Department of Building Process and Building Physics, Akademicka 5, 44-100 Gliwice, Poland
Grzegorz Dzido: Faculty of Chemistry, Department of Chemical Engineering and Process Design, Silesian University of Technology, ks. M. Strzody 7, 44-100 Gliwice, Poland
Monika Czop: Faculty of Energy and Environmental Engineering, Department of Technologies and Installations for Waste Management, Silesian University of Technology, Konarskiego 18, 44-100 Gliwice, Poland
Małgorzata Kajda-Szcześniak: Faculty of Energy and Environmental Engineering, Department of Technologies and Installations for Waste Management, Silesian University of Technology, Konarskiego 18, 44-100 Gliwice, Poland

Energies, 2025, vol. 18, issue 21, 1-34

Abstract: This study investigates the valorization of municipal solid waste incineration (MSWI) residues—specifically bottom ash with slag (BA + S) and fly ash (FA)—through alkaline activation in geopolymer and cementitious systems. The research demonstrates that alkali activation significantly improves mechanical properties, with compressive strengths up to 45.9 MPa for cement mortars and 33.2 MPa for geopolymers. A key innovation includes the quantification of hydrogen gas release during activation, with up to 72.5 dm 3 /kg H 2 from BA + S, offering insights into binder design and potential green hydrogen recovery. Environmental leachability assessments confirmed that activated BA + S immobilizes heavy metals effectively, although FA showed higher barium and lead leaching. Morphological analysis (SEM, granulometry) revealed microstructural changes enhancing reactivity. Additionally, a practical swelling test is proposed for early detection of expansion risk. The findings contribute to the development of sustainable, high-performance binders from waste, with implications for circular economy and energy valorization strategies.

Keywords: alkali activation; MSWI residues; hydrogen evolution; degassing; slag; ash–slag mixture; circular economy; construction safety; energy valorization; aluminum reactivity (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2025
References: Add references at CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/1996-1073/18/21/5857/pdf (application/pdf)
https://www.mdpi.com/1996-1073/18/21/5857/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:18:y:2025:i:21:p:5857-:d:1789061

Access Statistics for this article

Energies is currently edited by Ms. Cassie Shen

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().