Recycling of Discarded Photovoltaic Modules Using Mechanical and Thermal Methods

Abstract

Photovoltaic installations have experienced very significant growth worldwide since the early 2000s, driven by growing industry and government interest in mitigating climate change, decarbonization, and increasing energy demand. The most prevalent worry with photovoltaic (PV) panels is that their age is limited and they will eventually need to be decommissioned. With the expansion of PV production capacity worldwide, a large amount of PV panel waste will be generated in the future. Since PV panels contain heavy metals such as lead, cadmium and tin, this can have a significant impact on the environment. In addition, they also contain valuable metals (e.g. silver, gallium, indium and germanium) and standard materials (e.g. aluminum, glass) that represent a valuable opportunity when recovered. Developing a sustainable, environmentally friendly recycling process and maximizing the recovery of components from PV panels at the end of their life is expected to solve the PV waste problem. In this work, three alternative methods for recycling silicon-based (mono/polycrystalline) PV panels were investigated based on a combination of mechanical and thermal processes. The three alternative methods are a hammer crusher followed by thermal treatment and square sieve, a shredder crusher followed by thermal treatment and square sieve, and thermal treatment followed by a slotted sieve. X-ray diffraction (XRD) and X-ray fluorescence (XRF) were performed to evaluate the properties of the obtained products. The results showed that thermal treatment followed by slotted sieve is the most effective method for direct glass recovery for all types of photovoltaic modules studied.