Physical and chemical treatment of end of life panels: an integrated automatic approach viable for different photovoltaic technologies

Different kinds of panels (Si-based panels and CdTe panels) were treated according to a common process route made up of two main steps: a physical treatment (triple crushing and thermal treatment) and a chemical treatment. After triple crushing three fractions were obtained: an intermediate fraction (0.4-1 mm) of directly recoverable glass (17%(w/w)); a coarse fraction (>1 mm) requiring further thermal treatment in order to separate EVA-glued layers in glass fragments; a fine fraction (<0.4 mm) requiring chemical treatment to dissolve metals and obtain another recoverable glass fraction. Coarse fractions (62%(w/w)) were treated thermally giving another recoverable glass fraction (52%(w/w)). Fine fractions can be further sieved into two sub-fractions: <0.08 mm (3%(w/w)) and 0.08-0.4 mm (22%(w/w)). Chemical characterization showed that 0.08-0.4 mm fractions mainly contained Fe, Al and Zn, while precious and dangerous metals (Ag, Ti, Te, Cu and Cd) are mainly present in fractions <0.08 mm. Acid leaching of 0.08-0.4 mm fractions allowed to obtain a third recoverable glass fraction (22%(w/w)). The process route allowed to treat by the same scheme of operation both Si based panels and Cd-Te panels with an overall recycling rate of 91%.