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The increasing production of computers, the progress in their performance, and the shorter time between innovation and production has led to increasing numbers of obsolete products. It has thus become necessary to recover some materials from old computers and to protect the environment from a new type of pollution. Such recycling is difficult because of the diversity of polymeric materials used, e.g., thermoplastics (polystyrene or acrylonitrile-butadienestyrene) and thermosets (epoxy resins), and the relatively high levels of flame retardants (halogen-and nitrogencontaining compounds) added during production. Pyrolysis seems to be a suitable way to recover materials and energy from such waste without component separation if an efficient method for reducing toxic compounds can be applied. In this study, the pyrolysis of plastic and thermoset fractions (keyboards, casings, printed circuit boards, and mixtures thereof) of used computers was studied by thermogravimetry and batch reactor pyrolysis. The degradation products were separated into three fractions, solid, liquid, and gaseous, each of them being characterized by suitable methods such as gas chromatography (GC-MSD, gas chromatography-mass spectrometry detection; GC-AED, gas chromatography-atomic emission detection), infrared (FT-IR) and 1H-NMR (nuclear magnetic resonanace) spectroscopy, and elemental analysis. It has been established that most of the halogens, nitrogen, and sulfur is concentrated in the residue. However, the elimination of hazardous toxic compounds, mainly those containing bromine, is necessary before being able to safely use the pyrolysis oils as fuels or in refinery or petrochemical industry flows.

Here, we focused on the pyrolysis of printed circuit boards (PCBs) from used computers using various combined procedures of thermal and catalytic pyrolysis and dehalogenation (absorption) aiming to obtain pyrolysis oils with low amounts of heteroatoms (Br, Cl, N, and O) that might be suitable for use as fuel or feedstock. The composition of degradation oils was established by suitable methods, such as gas chromatography (GC−MSD and GC−AED), 1H nuclear magnetic resonance (NMR), and Fourier transform infrared spectroscopy (FTIR), and common methods for the analysis of petrochemical products. It has been found that catalytic cracking and dehalogenation procedures are simple and effective methods to convert PCBs into some useful products.