Product classes characterization at micro-scale level applied to granular wastes fractions < 20 mm: a case-study

Abstract A product class characterization was requested on some plastic granular waste samples, already reduced in fine form with particles < 20 mm, derived from waste electrical wires and PC cables. The product class discrimination was worked out by visual characterization with the aid of optical stereomicroscopy and confirmation by electron scanning microscopy (SEM) and microanalysis. Characterization at a micro-scale level evidenced predominance of plastic materials with presence of metal wires, paper, textile and glass fibres at residual levels in the main fraction (0.5–4 mm). The fractions < 0.5 mm, when present, cannot easily be distinguished at sight and only approximate qualitative information can be extracted by SEM analysis. The described approach has been carried out effectively due to major shape and material differences between plastic particles and metal wires and other materials. However, this approach may not work in every case, or it may not lead to usable results with every type of waste.