Impact of silicon and other contaminants on the melting process in photovoltaic glass recycling

The global growth of photovoltaic (PV) power generation has led to an anticipated increase in the disposal of panels, with glass, which accounts for 76 % of panel weight, becoming a key focus for recycling efforts. However, the feasibility of glass melting recycling remains unclear. When recovered glass from PV panels is contaminated with silicon from the cells, it is hypothesized that Si may reduce glass component oxides during the glass melting process. This study investigates the reaction between PV panel glass and contaminants generated during its disassembly, especially antimony oxide in PV glass and Si contaminants during the glass melting recycling process. PV glass containing reagent that found in PV panel parts was subjected to high-temperature treatment, and the resulting samples were analyzed using X-ray diffraction. Additionally, redox reactions between glass-component oxides and these elements were investigated through chemical thermodynamics calculations. The results indicated that Cu turned the glass blue, and Si and Al turned it gray. An addition of 0.1 mass% Si turned the glass yellow, which is attributed to the reduction of sulfur oxide. With more Si added, antimony oxide was reduced and excess Si remained. The presence of Si induced defects during the melting process, highlighting the critical need to prevent Si contamination when recycling PV glass. These findings offer valuable insights into optimizing PV glass recovery methods for manufacturing various recycled products.