Effect of electric pulse treatment on silver recovery from spent solar panel sheet by acid-leaching

Abstract

AbstractThe number of spent photovoltaic (PV) panels is expected to increase significantly in the coming decades. Crystalline silicon photovoltaic cells contain materials, such as silver, copper, aluminum, silicon, glass, and resins. Approximately 600 g/t of silver is used as a current collector, so-called finger wires, in photovoltaic modules; therefore, silver recovery is an important issue. To establish an effective recycling process for spent photovoltaic panels, a wire explosion method using high-voltage pulsed discharge was investigated to expose and separate silver selectively. In this study, acid-leaching experiments were conducted on spent ground photovoltaic panels with and without electric pulse treatment to verify the effect of the pulse treatment on acid-leaching of silver. Electric pulse treatment improved both the maximum silver recovery rate and leaching speed. Leaching experiments were also conducted using photovoltaic samples from three different silver exposure states. It can be concluded that silver recovery was strongly controlled by the exposure state and that the electric pulse treatment could effectively promote silver exposure of spent PV panels, even in the region where the silver wires were not energized.