Millions of photovoltaic panels have been installed in Europe in the past twenty years. The average life of a panel is about 25 years and, for this reason, in Italy there will be soon more than 50 million panels that will require disposal. In order to recover the materials that they contain, various treatment technologies are available nowadays, even if most of them have not yet been industrialized. The panels installed are mostly (>80%) based on mono- or poly-crystalline silicon and they are composed, apart from silicon, also of glass, copper, aluminum, tin and silver. The methods of treating photovoltaic waste can be divided into: mechanical, thermal and chemical or a combination of these. In this paper, the existing methods are analyzed and compared. Nowadays the mechanical method is the most implemented as it is the less expensive. Nevertheless, the silicon cannot be valorized because it is recovered in powder with high contamination due to the mechanical grinding. On the other hand, pure chemical treatment cause also great damages to the silicon because of EVA swelling. The use of the thermo-chemical treatment, is therefore the most promising in order to recover and reuse the silicon. This process has been tested during 2019 on a pre-industrial scale (ReSiELP project) and comprise a heating treatment to burn polymeric fraction combined with materials separation and chemical treatment of the silicon cells. The results of the constructed pilot plant, that are briefly reported, showed the feasibility of recovering several raw materials as well as different issues in the silicon purification process. Finally, the Life Cycle Assessment (LCA) of the studied process, pointed out the importance of the proper heat treatment design and the advantage of silver and silicon recovery, from an environmental point of view. © 2022 Associazione Italiana di Metallurgia. All rights reserved.

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