University of Oulu

Yliniemi, J., Pesonen, J., Tanskanen, P. et al. Waste Biomass Valor (2017) 8: 339.

Alkali activation-granulation of hazardous fluidized bed combustion fly ashes

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Author: Yliniemi, Juho1; Pesonen, Janne2; Tanskanen, Pekka3;
Organizations: 1Fibre and Particle Engineering, University of Oulu, Oulu, Finland
2Sustainable Chemistry, University of Oulu, Oulu, Finland
3Process Metallurgy, Faculty of Technology, University of Oulu, Oulu, Finland
4Inorganic Chemistry, Center for Molecular Materials, Oulu, Finland
5Department of Chemical Engineering, Delft University of Technology, Delft, The Netherlands
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 1.4 MB)
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Language: English
Published: Springer Nature, 2017
Publish Date: 2019-11-26


The increasing amount of fluidized bed combustion (FBC) ash is putting pressure on researchers to invent novel methods for utilizing the ash. The low reactivity and heavy metal content constrict the use of FBC ash in the same way as coal ash from pulverized combustion. Four FBC fly ashes from different power plants were granulated with sodium silicate solution in order to produce artificial aggregates. All aggregates matched the definition for lightweight aggregate according to the EN 13055–1 standard. The strongest aggregates were produced from fly ashes that had the highest X-ray amorphous material content and the highest amount of selectively soluble SiO₂ and Al₂O₃. However, the same leaching problem (leaching of the anionic species) as with coal fly ashes was observed with the FBC fly ashes. The simultaneous high shear granulation and alkali activation of FBC ashes showed that artificial aggregates with satisfactory physical properties, such as density and strength, can be obtained even from low-reactive fly ashes that contain heavy metals.

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Series: Waste and biomass valorization
ISSN: 1877-2641
ISSN-E: 1877-265X
ISSN-L: 1877-2641
Volume: 8
Issue: 2
Pages: 339 - 348
DOI: 10.1007/s12649-016-9580-7
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
116 Chemical sciences
Copyright information: © Springer Science+Business Media Dordrecht 2016. This is a post-peer-review, pre-copyedit version of an article published in Waste and Biomass Valorization. The final authenticated version is available online at: