Silicon Recovery from Solar Module Waste by a Physical Method

Abstract

This paper describes the physical process used to recover silicon from a solar module, where the solar cell recovery rate (87.4 %) was determined under optimized process conditions. This physical recycling method requires a particle separation process because selective separation of the recovered materials is difficult, and the recovery rate and purity of the recovered materials can be low after the initial particle separation. In this study, the recovery rate was determined with respect to the crushing time and rotational speed of the cutter mill as well as the amplitude and separation time of the sieving machine, which were optimized to increase the Si recovery rate. In addition, an etching process was used to recover high-purity Si from the solar cells. To determine whether Ag and Al were removed from the recovered Si, XRD analysis was performed to confirm the measured Si peak and small TiO 2 peak, and ICP-MS analysis was performed to confirm the purity of the recovered Si, which was found to be of 3N grade.