Toward recycling unsortable post consumer WEEE stream C 2021 Journal of C

The work reported here is the first study aimed at providing a full screening of a real unsortable non-recycled post-consumer WEEE stream free of brominated flame retarded plastics, separated using on-line X-ray detection, toward its recycling. In the existing sorting lines, up to 40% of plastics from waste electrical and electronic equipment (WEEE) stream can be rejected, herein named unsortable plastics. To have the most representative homogeneous sample for physico-chemical characterizations, a sampling method was developed to overcome the heterogeneity of the investigated 500 kg batch. The batch screening on both representative samples (~500 mm size) and 100 plastic fractions (~20 mm size), by means of routine techniques used in the plastic industry, has allowed to quantify reliably the main polymers included in the studied batch; ~50% styrene-based polymers, ~15% polypropylene (PP), ~15% polycarbonate (PC), ~1e4% polyamide (PA), polyethylene (PE), polyvinyl chloride (PVC), poly (ethylene terephthalate) (PET), poly (methyl methacrylate) (PMMA) and ~8% of multi-layer plastics, paints and thermosets. The identification of the ~8.0% inorganic phase by X-ray fluorescence spectrometry revealed the presence of several additives/charges commonly incorporated in plastic materials, such as calcium carbonate and talc. The studied batch was then subjected to electron beam irradiation at 50 and 200 kGy doses, as a means of compatibilization between the batch components.