Development of physical recycle process of end of life photovoltaic panels for glass and metal recovery

Background: To date, the recycling of end-of-life photovoltaic panels (PVs) is a topic of great interest due to the increasing use of this technology and the disposal of PVs is expected to become a relevant environmental issue in the coming decades. This requires proper management of the PVs to maximize the recovery of raw materials. Objective: In this work, a new physical process was developed for recycling of first-generation photovoltaic panels. The process is based on a mechanical operation developed with three different variants, methods B, F and S respectively. The characterization of the fractions obtained made it possible to evaluate which was the best method for recovering metals, silicon and fairly pure glass. Process: The process involved an initial phase of manual removal of the junction box (1.1 % w) and cables (0.9 % w). Subsequently, the frame was removed and then sent to a blade crusher obtaining the aluminum fraction (9.4 % w). Panel, without frame, was subjected to the mechanical operation with the S method, which allowed the selective removal of the backsheet (4.7 % w), the glass with a layer of EVA (74.9 % w) and of a crushed material composed of EVA, cells and contacts (10 % w). A high quality pure glass (74 % w) was obtained, after passing through a tumbling machine which removed the EVA fragments. Finally, to mechanically separate contacts (0.4 % w) from main fraction (9.6 % w), the crushed material containing EVA, cells and contacts, was sieved with a 1mm sieve. Conclusion: Through characterization of the fractions produced by using the developed B, F and S mechanical methods, it was verified that the S method was the only that managed to selectively separate the backsheet and offered the best results in terms of selective separation. In particular, the final fraction that such process produces correspond to 9.6% by weight of the panel, of which approximately 5.8% is EVA and the remaining 3.8% is composed of Si and metals used in the cell (Al, Ag, Zn, Pb, Sn, Cu, Fe). This fraction is ideal to recover precious metals and silicon by a chemical attack or a thermal process.