High-efficiency and environmentally friendly copper recovery from waste copper clad laminate and its pyrolysis behavior through a novel low-temperature rotary furnace process

Abstract

Recycling metal materials from waste copper clad laminate (WCCL) in a pollution-free and efficient way holds significance for the comprehensive utilization of resources. This study used waste paper-laminated copper clad laminate (PL-WCCL) as a raw material and conducted pyrolysis in a rotary furnace. The variations of the functional groups in PL-WCCL and the non-metallic part of PL-WCCL under different conditions were analyzed by thermogravimetric coupled Fourier transform infrared spectroscopy (TG-FTIR). The liquid-phase products were analyzed using gas chromatography-mass spectroscopy (GC-MS), and the morphology of the solid-phase products and the contact surfaces of the metal and non-metal parts of PL-WCCL were determined by photography and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS). The results indicate that the maximum weight loss rate of PL-WCCL is 62.48%, and the activation energy (E) is 29.84 kJ mol⁻¹. During the pyrolysis, copper can lower the beginning reaction temperature, facilitate the release of bromine and chlorine, accelerate the synthesis of lighter hydrocarbons, and increase the release of CO₂. The optimal conditions are as follows: a retention time of 60 min at 150 °C and a filling capacity of 51.95 g L⁻¹, resulting in a 100% separation rate of metal, without requiring crushing. The liquid organic products obtained were merely phenol and o-cresol. This research introduced a comprehensive green processing method utilizing a rotary furnace as the reactor to effectively extract metallic copper from PL-WCCL.