Recovery of Silicon via Using KOH-Ethanol Solution by Separating Different Layers of End-of-Life PV Modules

With the rapid increase of photovoltaic (PV) system production and installation, the recycling of end-of-life PV modules has become an important issue. In this paper, the recovery of Si by separating the layers of end-of-life PV modules using KOH-ethanol solution was investigated. Compared with traditional swelling or dissolving reagents (such as benzene and trichloroethylene), KOH-ethanol is a green reagent with low environmental toxicity. The experiments explored the effect of different alkalis, module sizes, temperatures, KOH concentrations, and solid-to-liquid ratios on the separation ratio of the PV modules. The mechanism for separating these layers was also studied. Under optimal conditions, the layers of these PV modules can be completely separated in 3 h, and oxidation of the recovered Si wafer can be controlled. Hence, this method of recycling PV modules is of great significance for environmental protection and resource utilization.