Pyrolysis and utilization of nonmetal materials in waste printed circuit boards: Debromination
pyrolysis, temperature-controlled condensation, and synthesis of oil-based resin
The rapid replacement of electric and electronic equipment has produced large amount
of waste printed circuit boards (WPCBs). At present, physical and mechanical methods
are widely used to recover valuable metals from WPCBs. Unfortunately, produced nonmetal
materials (NMMs) were typically hazardous waste and were usually disposed by landfill.
Considering the characteristics of structure and composition of NMMs, debromination
pyrolysis was regarded as the appropriate technique to decompose organics. However,
pyrolysis oil and pyrolysis residue were still typically hazardous and difficult to
disposal or recycle. Hence, we proposed a novel integrated method to reuse NMMs. The
results showed that temperature-controlled condensation method was effective to separate
pyrolysis oil. Besides, bromine was removed from organics and formed CaBr2. Pyrolysis
oil was used to synthesize oil-based resin. FT-IR, H-1 and C-13 NMR and TG analysis
results indicated that oil-based resin had the same structure and thermostability
with commercial resin, which suggested that oil-based rein had economic value. In
addition, CaBr2 in residual could be recycled by water leaching and filter residues
can be used as ideal reinforcing material for building materials. This study raises
a comprehensive method to utilize NMMs and recover value materials effectively, sustainably
and environmentally friendly.