X-ray fluorescence sorting of non-ferrous metal fractions from municipal solid waste incineration bottom ash processing depending on particle surface properties

Kerstin Pfandl, Bastian Küppers, Stefanie Scheiber, Gerhard Stockinger, Johannes Holzer, Roland Pomberger, Helmut Antrekowitsch, Daniel Höllen

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A heavy non-ferrous metal fraction (< 50 mm) of municipal solid waste incineration bottom ashes from wet-mechanical treatment was separated by screening, magnetic separation and eddy-current separation into ferrous metals, non-ferrous metals and residual sub-fractions. The non-ferrous metal fractions were divided and subjected to (i) a washing process, (ii) dry abrasion and (iii) no mechanical pre-treatment to study the effect of resulting different surface properties on a subsequent X-ray fluorescence sorting into precious metals, zinc, copper, brass, stainless steel and a residual fraction. The qualities of the X-ray fluorescence output fractions were investigated by chemical analyses (precious metal fraction and the residual fraction), pyrometallurgical tests and subsequent chemical analyses of the metals and slags produced by the melting processes (zinc, copper, brass and stainless steel fraction). Screening directs brass and stainless steel primarily into the coarser fractions, while copper and residual elements were rather transferred into the finer fractions. X-ray fluorescence sorting yielded zinc, copper, brass, stainless steel and precious metals fractions in marketable qualities. Neither a negative nor a positive impact of mechanical pre-treatment on the composition of these fractions was identified. Solely the yield of the brass fraction in the grain size 16–20 mm decreased with increasing mechanical pre-treatment. The pre-treatment also had no impact on yield and quality of the products of pyrometallurgical tests.

Original languageEnglish
Pages (from-to)111 - 121
Number of pages11
JournalWaste management & research
Issue number2
Publication statusPublished - 1 Feb 2020


  • Bottom ash
  • X-ray fluorescence sorting
  • heavy non-ferrous metals
  • mechanical processing
  • metal recovery
  • metal recycling
  • municipal solid waste incineration residues
  • surface properties

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