A new approach for separating copper, tin, and lead from photovoltaic ribbon wastes

Abstract

Recovery of valuable lead (Pb), copper (Cu), and tin (Sn) from photovoltaic (PV) ribbon waste is essential for the sustainability of the PV industry. In this study, a two-step physical process comprising molten separation and vacuum distillation was proposed and used to recover Cu, Sn, and Pb from PV ribbon waste. First, Sn–Pb coatings (melting point: 451–456 K) were effectively recovered from Cu substrates (melting point: 1356.4 K) through melt separation at 723 K for 4 h, yielding a Sn–Pb alloy with low Cu contamination (1.23 wt%) and Cu strips with minimal residual Sn (1.89 wt%) and Pb (1.23 wt%). Second, the Cu-containing Sn–Pb alloy at 1423 K and 50 ± 10 Pa was selectively volatilized through vacuum distillation, yielding ultra-pure Pb (Cu: 8 ppm, Sn: 66 ppm) and 99.7 % separation efficiency. Cu and Sn remained in the residual alloys due to their comparable vapor pressures. This work provides a green, sustainable method for separating Pb, Cu, and Sn from photovoltaic strip wastes without generating carbon, waste acid, and waste gas throughout the entire production process, which is in line with the goal of a circular economy.