Characterization of products recycling from PCB waste pyrolysis

Recycling of printed circuit board (PCB) waste is an important subject not only for the protection of environment but also for the recovery of valuable materials. A preliminary study of the possibilities of pyrolysis for recovering valuable products and energy from PCB waste was presented. Pyrolysis of PCB waste was performed on a fixed-bed reactor. The properties of the pyrolytic oil and residue were investigated. The oil was characterized by various chromatographic and spectroscopic techniques. Chromatographic and spectroscopic studies on the pyrolysis oil showed that it contained significant concentrations of phenol, as well as 4-(1-methylethyl)-phenol and could potentially be recycled into phenolic resin. The oil was then polymerized with formaldehyde under basic conditions to synthesize pyrolysis oil-based resin. FT-IR and ¹H NMR analysis revealed that the aromatic nuclei in the oil were linked by ether linkages or methylene bridges after polymerization. The pyrolysis residues obtained from PCB waste were very friable, prone to delamination and could be easily liberated for carbon, glass fiber, and metallic fractions. A controlled combustion of the solid phase allowed the formation of glass fibers unaltered, which could be recycled.