Heavy metals leaching in bottom ash and fly ash fractions from industrial-scale BFB-boiler for environmental risks assessment

Research output: Contribution to journalArticleScientificpeer-review

Researchers

Research units

  • Swedish University of Agricultural Sciences
  • Tokyo Institute of Technology
  • Stora Enso
  • City of Kemi

Abstract

The bottom ash and fly ash from the co-combustion of wood residues and peat at a bubbling fluidised bed boiler (296 MW) contained only quartz (SiO2), microcline (KAlSi3O8) and albite (NaAlSi3O8). Thus, X-ray powder diffraction (XRD) was not useful for clarifying the difference in the release of associated heavy metals from ash matrices. In order to assess the release of heavy metals from ashes under changing environmental conditions, they were sequentially extracted and fractionated by the BCR-procedure into acid soluble/exchangeable (CH3COOH), reducible (NH2OH-HCl) and oxidizable (H2O2/CH3COONH4) phases. The CH3COOH extractable fraction in conjunction with the total heavy metals concentrations were used to calculate the risk assessment code values for heavy metals leaching from the ash matrix. The leaching studies indicate that the heavy metals in the bottom ash and fly ash are bound to different fractions with different strengths. From the environmental and utilization perspectives, heavy metals in ashes posed different levels of environmental contamination risk. Only As in the bottom ash posed a very high risk. High risk metals were Cd in the bottom ash as well as As, Cd and Se in the fly ash.

Details

Original languageEnglish
Pages (from-to)256-264
Number of pages9
JournalTRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
Volume26
Issue number1
Publication statusPublished - Jan 2016
MoE publication typeA1 Journal article-refereed

    Research areas

  • bottom ash, fly ash, BCR, extraction, heavy metals, risk assessment code, SEQUENTIAL EXTRACTION PROCEDURE, SURFACE SEDIMENTS, CHEMICAL-EXTRACTION, SOLID-WASTE, SOIL, SPECIATION, MOBILITY, SAMPLES, CHINA

ID: 1493785