Metal recovery from waste printed circuit boards by flotation technology with non-ionic renewable collector

Abstract Using waste oil as renewable collector, flotation method was proposed to recover metal from waste printed circuit boards (WPCBs). The flotation mechanism was revealed by functional group composition, which was analyzed by infrared spectrometer (FT-IR) and X-ray photoelectron spectroscopy (XPS). Elemental analysis shows that Cu and Fe in WPCBs are mainly concentrated in 1–0.5 mm and −0.5 mm respectively with ideal dissociation, which is verified by SEM + EDS analysis. Waste oil from kitchen waste was purified and used as flotation collector to realize the separation of metal particles and non-metal particles. The effect of collector dosage on the flotation behavior of 1–0.5 mm and −0.5 mm was analyzed respectively. Flotation results show that metal content in concentrate increases with the increase of collector dosage, which is accompanied by recovery decrease. For 1–0.5 mm, concentrate with 47.77% Cu and 91.15% recovery was obtained with 8 kg/t collector. For −0.5 mm, Fe and Cu content achieved 40.01% and 8.03% respectively, with recovery of 71.99% and 91.61% when the collector dosage was 1 kg/t. The functional group composition was determined by FT-IR and the carbon-based functional group content was tested by XPS, which illustrates the adsorption of the collector on the particle surface. The physical methods proposed in this study contribute to the cleanliness of the metal recovery process and realize the resource utilization of two kinds of waste.