The most difficult materials to recover from solar panels are typically the internal components embedded within tightly bonded layers and sealed with adhesives or polymers. Specifically:
- Silver and internal copper: These valuable metals are present only in small amounts inside the solar cells, making their recovery challenging due to their dispersion and the complexity of separating them from silicon and other materials.
- Silicon solar cells: The silicon wafers are encapsulated within polymer layers and glass, which are tightly sandwiched to withstand weather exposure. This multilayer construction complicates the disassembly and extraction of silicon.
- Polymer layers and adhesive encapsulants (like EVA): These seal the solar cells and glass together but require high temperatures (around 500 °C) or expensive organic solvents for removal. Removing the EVA and other polymers is energy-intensive and generates hazardous waste, posing a significant challenge to recycling processes.
- Toxic metals such as lead and cadmium: Present in some solar panels, these hazardous materials require careful handling and specialized methods for safe recovery and disposal.
By contrast, materials such as glass (about 75% of panel weight), aluminum frames, copper wiring, and plastic junction boxes are relatively easier to recycle due to established recycling industries.
The main recycling difficulty lies in loosening the adhesive bonds and separating the tightly integrated layers to efficiently extract the valuable but small and dispersed internal metals and silicon, without excessive energy use or hazardous byproducts. Innovative methods and plants are being developed to improve separation and recovery, but the complexity of the layered structure remains the primary barrier.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/what-materials-are-most-difficult-to-recover-from-solar-panels/
