Kinetic Investigations of the Electrochemically Assisted Leaching of Metals for the Recycling of Photovoltaics

Abstract

To describe and predict the leaching of Ag, Cu and Sn from waste photovoltaic modules with an electrochemical-assisted process kinetic investigations were performed. In this process, peroxydisulfate is generated from sulfuric acid to oxidize metals. It was found that under the reaction conditions peroxymonosulfate is formed as well and has a major contribution to the leaching process. For Ag, autocatalytic decomposition of the leaching reagents is determined to be a limiting step while for Sn passivation influences the process. The leaching is modeled for three different reaction types, a batch reaction, the reaction in a static H-cell with continuous generation of S₂O₈2− and a fed-batch reaction with an electrochemical flow cell for the production of peroxydisulfate.