Experimental, cost and waste analysis of recycling process for crystalline silicon solar module

Photovoltaic (PV) technology is projected to supply nearly one fourth of the power need worldwide by year 2050. However, owing to the various toxic as well as valuable materials contained in the panel makes the technology questionable after the end of life. Therefore, there is a need to recycle and recover materials from the solar panels. This study explores different aspects of recycling like recovery of materials, cost involved, and waste generated. Firstly, thermal process was optimized for the maximum utilization of energy and space inside the muffle furnace with which a total of 800 gm solar panel pieces, placed in five stacks, successfully processed in a single run. Following that, solar cell pieces and connecting wires were separated and treated with optimized solution of KOH, HNO 3 for extraction of Al and Ag, respectively. Connecting wires treated with optimized solution of 4 M HCl at 80 degree celsius to recover Cu wires and liberate Pb and Sn ions. The acidic waste water generated during the process was neutralized using Ca(OH) 2 . Addition of Ca(OH) 2 to waste water not only maintained the pH of water but also lead to the precipitation of toxic metal ions like Pb. Cost analysis has shown that the input cost is higher than the output cost, majority of which resulted from the zinc dust employed to recover Sn and Cu. CuO powder and K 2 SO 4 crystals were also obtained as the by-product. X -Ray Fluorescence (XRF) spectroscopy revealed that majority of solid waste generated is toxic in nature due to Pb.