Co-pyrolysis of waste printed circuit boards with iron compounds for Br-fixing and material recovery

Waste printed circuit boards (WPCBs) were co-pyrolyzed with iron oxides and iron salts. Solid, liquid, and gaseous products were collected and characterized. Co-pyrolysis with FeCl2, FeCl3, or FeSO4 was able to increase the yield of liquid product which was rich in phenol and its homologues. Also, the addition of co-pyrolysis reagents reduced the release of brominated organics to liquid as Br was either fixed as FeBr3 in solids or released as HBr. In particular, FeCl2 showed the best ability to reduce the release of Br-containing organics to liquid compared with FeCl3 and FeSO4. Solid residuals were rich in iron oxides, glass fibers, and charred organics with surface areas of 20.6-26.5 m(2)/g. CO2 together with a small amount of CH4 and H-2 were detected in the gaseous products. Overall, co-pyrolysis could improve the quantity and quality of liquid oil which could be reused as chemical or energy sources. Pyrolysis of waste printed circuit board was promising as a method for recycling.

Automated summary

Co-pyrolysis with iron oxides and iron salts can increase the yield of liquid product rich in phenol, reduce the release of brominated organics to liquid, and produce solid residuals rich in iron oxides, glass fibers, and charred organics. Gaseous products contain CO2, CH4, and H2.