Alkali Activation–Granulation of Hazardous Fluidized Bed Combustion Fly Ashes

Juho Yliniemi, Janne Pesonen, Pekka Tanskanen, Olli Peltosaari, Minna Tiainen, Henk Nugteren, Mirja Illikainen*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

6 Citations (Scopus)
20 Downloads (Pure)

Abstract

Abstract: 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. Graphical Abstract: [Figure not available: see fulltext.]

Original languageEnglish
Pages (from-to)1-10
JournalWaste and Biomass Valorization
DOIs
Publication statusPublished - 2017

Bibliographical note

Accepted Author Manuscript

Keywords

  • Alkali activation
  • Fluidised bed combustion
  • Fly ash
  • Granulation
  • Heavy metal
  • Lightweight aggregate

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