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

Tutkimustuotos: Lehtiartikkelivertaisarvioitu

Tutkijat

Organisaatiot

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

Kuvaus

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.

Yksityiskohdat

AlkuperäiskieliEnglanti
Sivut256-264
Sivumäärä9
JulkaisuTRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
Vuosikerta26
Numero1
TilaJulkaistu - tammikuuta 2016
OKM-julkaisutyyppiA1 Julkaistu artikkeli, soviteltu

ID: 1493785