One-pot wet ball-milling for waste wire-harness recycling

In this study, we developed a one-pot wet ball-milling method for the recovery of highly pure copper wire, poly(vinyl chloride) (PVC) coating, and diisononyl phthalate (DINP) plasticizer from waste wire harnesses. n-Butyl acetate, acetone, or ethyl acetate was used as the solvent to simultaneously extract the DINP and separate the Cu and PVC, by swelling the PVC coating and physically impacting the cables with milling balls, achieving the whole process in one pot. The swelling ratios suggested the order of solvent power for PVC as n-butyl acetate > acetone > ethyl acetate at similar to 25 degrees C after 80-min submersion; while on increasing temperature, this order changed to acetone > n-butyl acetate > ethyl acetate. Due to the temperature rise induced by oblique ball-to-ball and ball-to-reactor collisions during milling, acetone exhibited the best separation efficiency, achieving complete separation of 20-cm-long cables in 40-min wet milling at 25 rpm, with the simultaneous, nearly quantitative recovery of DINP. Of the recovered Cu wires, nearly similar to 90% exceeded 10-cm lengths, which facilitated quantitative recovery in the separation step. Furthermore, 100% of the de-plasticized PVC was recovered, and similar to 85% of the solvent was regenerated by distillation for re-use.

Automated summary

In this study, a one-pot wet ball-milling method was developed for recovering highly pure copper wire, PVC coating, and DINP plasticizer from waste wire harnesses. The method used different solvents to extract DINP, separate Cu and PVC, and achieve nearly quantitative recovery of the components. The process allowed for efficient separation and recovery of materials with high purity and recyclability.