Study of electrostatic separation to concentrate silver, aluminum, and silicon from solar panel scraps

Abstract

PV modules generally contain several metals that are considered critical and/or strategic and can be recovered. They also contain harmful and toxic metals that pose a threat to the environment and human health, which makes the significance of recycling even greater. This study used mechanically processed waste Si–C (polycrystalline silicon) photovoltaic (PV) panels to obtain highly concentrated recycled metals of interest. The PV panels were comminuted and granulometrically separated before the concentration of the metals of interest could be studied in an electrostatic separator. Some parameters of the electrostatic separator were evaluated, such as the applied voltage, rotation speed of the roll, as well as distance and angle of the electrodes for better separation of the metals of interest (copper, silver, aluminum, and silicon). The results were evaluated by X-ray fluorescence analysis and the proportions of each element in the samples were compared. The results obtained showed that in the comminution and particle size separation process, the greatest mass of material (49.22%) is concentrated in the smallest particle size category, which is smaller than 0.5 mm. This particle size also has higher concentrations of silicon, silver, and aluminum. The best results with the electrostatic separator were obtained using an electric potential difference of 38 kV and a rotation speed of 75 rpm (rotation per minute), where it was possible to concentrate silicon, silver, and aluminum.