title: Optimized elemental analysis of fluorescence lamp shredder waste.
abstract: Fluorescence lamps contain considerable amounts of rare earth elements (REE). Several recycling procedures for REE recovery from spent lamps have been established. However, despite their economic importance, the respective recycling is scarce so far, with an REE recovery rate of less than 1%. A reliable analysis of REE and other relevant metals like Yttrium is crucial for a thorough and complete recovery process. This applies both to the solid matter and aqueous phase, since most of the recycling processes include wet-chemical steps. We tested seven different reagent mixtures for microwave-assisted digestion of fluorescent lamp shredder, including hydrofluoric acid, perchloric acid, and hydrogen peroxide. We determined the concentrations of 25 of the most relevant rare earth and other trace elements (Al, P, Ti, V, Cr, Fe, Ni, Cu, Ga, Ge, As, Y, Ag, Cd, Sn, Sb, La, Ce, Eu, Gd, Tb, W, Au, Hg, and Pb) in the respective dilutions. Two independent digestions, one a mixture of perchlorid/nitric/hydrofluoric acid and the other aqua regia, showed the highest concentrations of 23 of these elements, excluding only Sn and Tb. The REE concentrations in the tested lamp shredder sample (stated in g/kg) were 10.2 (Y), 12.1 (La), 7.77 (Ce), 6.91 (Eu), 1.90 (Gd), and 4.11 (Tb).
authors.affiliation: TUHH Hamburg University of Technology, Institute of Environmental Technology and Energy Economics, Harburger Schlossstrasse 36, D-21079 Hamburg, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Hobohm
authors.affiliation: TUHH Hamburg University of Technology, Institute of Environmental Technology and Energy Economics, Harburger Schlossstrasse 36, D-21079 Hamburg, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Kuchta
authors.affiliation: Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany. Electronic address: oliver.krueger@bam.de.
authors.forename: Oliver
authors.initials: O
authors.lastname: Krüger
authors.affiliation: University of Applied Sciences Berlin, Luxemburger Str. 10, 13353 Berlin, Germany. Electronic address: Sebastian.vanwasen@web.de.
authors.forename: Sebastian
authors.initials: S
authors.lastname: van Wasen
authors.affiliation: Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany. Electronic address: christian.adam@bam.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Adam
keywords: Elemental analysis; Microwave-assisted digestion; Rare earth elements; Yttrium