Investigation of the Optimal Recovery of Sn, Pb, Cu, and Ni from E-waste Generated Type of Slags in the Black Copper Processing Route

Electronic waste (e-waste) is the fastest-growing type of solid waste stream with increasing environmental concern. Fortunately, the presence of valuable metals in the e-waste make its recycling a feasible option. The black copper processing route is one of the most suitable for e-waste recycling. The slag-cleaning part of the process is important in separating certain metals like Sn from the generated slag. In this work, a synthetic e-waste slag was used in reduction experiments to obtain a better understanding of Cu, Ni, Sn, and Pb distribution in the metallic and slag phases in a slag-cleaning unit. Two master slags were synthesized: SiO ₂-Fe ₂O ₃-CaO-Al ₂O ₃ and SiO ₂-Fe ₂O ₃-CaO-Al ₂O ₃-Na ₂O. The master slags were doped with oxides of Cu, Ni, Sn, and Pb followed by the reduction experiments. The experimental conditions were highly reductive, resulting in the metals being highly distributed to the metallic phase. Amounts of < 2% Cu and Ni remained in the slag of the Na-free slag, while up to 6% Cu and 21% Ni remained in the Na-containing slag. High material loss was also observed, which was attributed to the volatilization of Pb and Sn. The material loss of Pb was significant, in the range 62–78%.