Sustainable alkali activated binders from a blend of biomass ash and iron sludge precursor

Abstract Biomass ash is produced as a by-product of boiler combustion and most of this ash is disposed of in landfills. Biomass ash has a relatively low reactivity and alkali activated ash systems have poor mechanical properties. The inclusion of Fe-rich material in the precursor composition would i...

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Main Authors: Darius Žūrinskas, Danutė Vaičiukynienė, Ruben Paul Borg, Laura Vitola
Format: Article
Language:English
Published: Nature Portfolio 2025-05-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-00455-y
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author Darius Žūrinskas
Danutė Vaičiukynienė
Ruben Paul Borg
Laura Vitola
author_facet Darius Žūrinskas
Danutė Vaičiukynienė
Ruben Paul Borg
Laura Vitola
author_sort Darius Žūrinskas
collection DOAJ
description Abstract Biomass ash is produced as a by-product of boiler combustion and most of this ash is disposed of in landfills. Biomass ash has a relatively low reactivity and alkali activated ash systems have poor mechanical properties. The inclusion of Fe-rich material in the precursor composition would increase the mechanical properties of alkali-activated binders. This study focuses on an alkali-activated binder made from blends of biomass fly ash from a power plant and iron sludge from a ship repair company. In the precursor blends, some of biomass fly ash were substituted by iron sludge, which consisted of high-volume Fe-rich compounds. After curing, the compressive strength was determined, and the strength values were explained by mineral composition and microstructure. Samples cured at higher temperature (at 60 °C for 24 h), iron sludge acted as a reactive component and reacted with NaOH to reduce its (NaOH) content in the system. For the samples cured at ambient temperature iron sludge acted as a less reactive component or like filler. Calcium aluminosilicate hydrate was not detected, but a higher amount of N-A/F-S-H and C-(A/F)-S-H gel formed compared to samples cured at higher temperature. Iron sludge incorporated into the matrix, making it more compact. These factors led to an increase in the strength values of the alkali-activated biomass fly ash incorporating the IS. The highest compressive strength of 9.8 MPa was achieved by samples cured at ambient temperature with 30% iron sludge. Thus, creating alkali activated binders is a promising way to use Fe-rich residues such as iron sludge from a ship repair company.
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spelling doaj-art-10d45786eb044a62916a2707d822cd9c2025-08-20T01:51:31ZengNature PortfolioScientific Reports2045-23222025-05-0115111310.1038/s41598-025-00455-ySustainable alkali activated binders from a blend of biomass ash and iron sludge precursorDarius Žūrinskas0Danutė Vaičiukynienė1Ruben Paul Borg2Laura Vitola3Faculty of Architecture and Civil Engineering, Kaunas University of TechnologyFaculty of Architecture and Civil Engineering, Kaunas University of TechnologyFaculty for the Built Environment, University of MaltaFaculty of Architecture and Civil Engineering, Kaunas University of TechnologyAbstract Biomass ash is produced as a by-product of boiler combustion and most of this ash is disposed of in landfills. Biomass ash has a relatively low reactivity and alkali activated ash systems have poor mechanical properties. The inclusion of Fe-rich material in the precursor composition would increase the mechanical properties of alkali-activated binders. This study focuses on an alkali-activated binder made from blends of biomass fly ash from a power plant and iron sludge from a ship repair company. In the precursor blends, some of biomass fly ash were substituted by iron sludge, which consisted of high-volume Fe-rich compounds. After curing, the compressive strength was determined, and the strength values were explained by mineral composition and microstructure. Samples cured at higher temperature (at 60 °C for 24 h), iron sludge acted as a reactive component and reacted with NaOH to reduce its (NaOH) content in the system. For the samples cured at ambient temperature iron sludge acted as a less reactive component or like filler. Calcium aluminosilicate hydrate was not detected, but a higher amount of N-A/F-S-H and C-(A/F)-S-H gel formed compared to samples cured at higher temperature. Iron sludge incorporated into the matrix, making it more compact. These factors led to an increase in the strength values of the alkali-activated biomass fly ash incorporating the IS. The highest compressive strength of 9.8 MPa was achieved by samples cured at ambient temperature with 30% iron sludge. Thus, creating alkali activated binders is a promising way to use Fe-rich residues such as iron sludge from a ship repair company.https://doi.org/10.1038/s41598-025-00455-yAlkali activated binderBlends of biomass fly Ash and iron sludgeAluminosilicate precursorIron-rich precursor
spellingShingle Darius Žūrinskas
Danutė Vaičiukynienė
Ruben Paul Borg
Laura Vitola
Sustainable alkali activated binders from a blend of biomass ash and iron sludge precursor
Scientific Reports
Alkali activated binder
Blends of biomass fly Ash and iron sludge
Aluminosilicate precursor
Iron-rich precursor
title Sustainable alkali activated binders from a blend of biomass ash and iron sludge precursor
title_full Sustainable alkali activated binders from a blend of biomass ash and iron sludge precursor
title_fullStr Sustainable alkali activated binders from a blend of biomass ash and iron sludge precursor
title_full_unstemmed Sustainable alkali activated binders from a blend of biomass ash and iron sludge precursor
title_short Sustainable alkali activated binders from a blend of biomass ash and iron sludge precursor
title_sort sustainable alkali activated binders from a blend of biomass ash and iron sludge precursor
topic Alkali activated binder
Blends of biomass fly Ash and iron sludge
Aluminosilicate precursor
Iron-rich precursor
url https://doi.org/10.1038/s41598-025-00455-y
work_keys_str_mv AT dariuszurinskas sustainablealkaliactivatedbindersfromablendofbiomassashandironsludgeprecursor
AT danutevaiciukyniene sustainablealkaliactivatedbindersfromablendofbiomassashandironsludgeprecursor
AT rubenpaulborg sustainablealkaliactivatedbindersfromablendofbiomassashandironsludgeprecursor
AT lauravitola sustainablealkaliactivatedbindersfromablendofbiomassashandironsludgeprecursor