Thermal decomposition characteristics of solar panels and their metal resource recovery

Against the backdrop of global efforts to achieve carbon neutrality, solar cells are recognized as a clean, renewable, and pollution-free power generation methodd, with significant advancements made in recent years. Crystalline silicon solar cell technology, being relatively mature, has become the mainstream in the market and is widely applied in various energy systems. However, the lifespan of crystalline silicon solar cells typically does not exceed 30 years. Without timely and proper recycling, the disposal of a large number of cells could lead to severe environmental issues, such as heavy metal pollution and the waste of valuable resources. Current methods for recycling solar panels mainly include chemical treatment, mechanical crushing, and thermal processing. Among these, pyrolysis has gained widespread industrial application due to its efficient recycling capabilities. Effects of different pyrolysis conditions on the recycling performance of solar panels are investigated experimentally, with a focus on the impact of pyrolysis temperature (400-600 ℃), heating rate (5-15 ℃/min), and pyrolysis atmosphere (N₂, CO₂, H₂) on recycling efficiency. The results indicate that a heating rate of 5 ℃/min, a pyrolysis temperature of 500 ℃, and a CO₂ atmosphere are the most favorable conditions for obtaining intact solar cells. Additionally, the yield of gaseous products significantly increases with higher pyrolysis temperatures and heating rates, particularly in a CO₂ atmosphere. Moreover, the increase in temperature notably enhances the production ratio of CH₄ and C₂H₄; in a H₂ atmosphere, the generation of C₂H₆, C₂H₄, and C₃H₆ is more pronounced. Higher temperatures and heating rates are found to improve the recovery efficiency, whereas excessive temperatures may reduce copper recovery rates. Finally, the economic benefits of solar panel recycling were assessed, revealing that the recovery of silver contributes over 50% to the overall economic return. This research provides essential insights for the development of more efficient and environmentally friendly solar panel recycling technologies in the future.