title: Quantification of the resource recovery potential of municipal solid waste incineration bottom ashes.
abstract: Municipal solid waste incineration (MSWI) plays an important role in many European waste management systems. However, increasing focus on resource criticality has raised concern regarding the possible loss of critical resources through MSWI. The primary form of solid output from waste incinerators is bottom ashes (BAs), which also have important resource potential. Based on a full-scale Danish recovery facility, detailed material and substance flow analyses (MFA and SFA) were carried out, in order to characterise the resource recovery potential of Danish BA: (i) based on historical and experimental data, all individual flows (representing different grain size fractions) within the recovery facility were quantified, (ii) the resource potential of ferrous (Fe) and non-ferrous (NFe) metals as well as rare earth elements (REE) was determined, (iii) recovery efficiencies were quantified for scrap metal and (iv) resource potential variability and recovery efficiencies were quantified based on a range of ashes from different incinerators. Recovery efficiencies for Fe and NFe reached 85% and 61%, respectively, with the resource potential of metals in BA before recovery being 7.2%ww for Fe and 2.2%ww for NFe. Considerable non-recovered resource potential was found in fine fraction (below 2mm), where approximately 12% of the total NFe potential in the BA were left. REEs were detected in the ashes, but the levels were two or three orders of magnitude lower than typical ore concentrations. The lack of REE enrichment in BAs indicated that the post-incineration recovery of these resources may not be a likely option with current technology. Based on these results, it is recommended to focus on limiting REE-containing products in waste for incineration and improving pre-incineration sorting initiatives for these elements.
authors.affiliation: Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby, Denmark. Electronic address: elia@env.dtu.dk.
authors.forename: Elisa
authors.initials: E
authors.lastname: Allegrini
authors.affiliation: Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby, Denmark.
authors.forename: Alberto
authors.initials: A
authors.lastname: Maresca
authors.affiliation: Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby, Denmark.
authors.forename: Mikael Emil
authors.initials: ME
authors.lastname: Olsson
authors.affiliation: Afatek Ltd., Selinevej 18, 2300 Copenhagen S, Denmark.
authors.forename: Maria Sommer
authors.initials: MS
authors.lastname: Holtze
authors.affiliation: Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby, Denmark.
authors.forename: Alessio
authors.initials: A
authors.lastname: Boldrin
authors.affiliation: Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby, Denmark.
authors.forename: Thomas Fruergaard
authors.initials: TF
authors.lastname: Astrup
mesh_terms: D017745:Incineration; D008670:Metals / Q000032:analysis*; D059027:Recycling; D014866:Waste Products / Q000032:analysis*
chemical_list: D008670:Metals; D014866:Waste Products
keywords: Bottom ashes; Critical elements; MSWI; Non-ferrous metals; REE; Recovery efficiency