Experimental Methodology for the Separation Materials in the Recycling Process of Silicon Photovoltaic Panels

Abstract

As the use of photovoltaic installations becomes extensive, it is necessary to look for recycling processes that mitigate the environmental impact of damaged or end-of-life photovoltaic panels. There is no single path for recycling silicon panels, some works focus on recovering the reusable silicon wafers, others recover the silicon and metals contained in the panel. In the last few years, silicon solar cells are thinner, and it becomes more difficult to separate them from the glass, so the trend is towards the recovery of silicon. In this paper, we investigate the experimental conditions to delaminate and recovery silicon in the recycling process, using a combination of mechanical, thermal, and chemical methods. The conditions of thermal treatment to remove the ethylene-vinyl acetate (EVA) layer were optimized to 30 min at 650 °C in the furnace. To separate silicon and metals, the composition of HF/HNO3 solution and the immersion time were adjusted considering environmental aspects and cost. Under the selected conditions, panels from different manufacturers were tested, obtaining similar yields of recovered silicon but differences in the metal concentrations.