PRE-TREATMENT AND CHARACTERIZATION OF PRINTED CIRCUIT BOARDS OF COMPUTERS WITH EMPHASIS IN METAL CONTENT

The recycling of waste electrical and electronic equipment (WEEE) is a worldwide challenge and this is one of the biggest issues debated on 21^st century, motivating the participation of governments research institutions and also the private sector in order to develop technologies based on the cleaner production (C + P) concept so that the eco-efficiency of the electronics industry is improved. In this work, the manual dismantling and mechanical processing steps, including grinding, magnetic and electrostatic separations were the procedures employed for this. Subsequently, the physical and chemical printed circuit board (PCB) characterizations was carried out by particle size classification and inductively coupled plasma optical emission spectroscopy/scanning electron microscopy-energy dispersive spectroscopy (ICP OES/SEM-EDS) analyses, respectively in order to confirm the release, separation and concentration of metal content. After magnetic separation, the percentages of the magnetic and non-magnetic fractions were 15.18 and 56.70%, respectively. In the magnetic fraction, the concentration of iron, nickel, silver and gold reached 1.26 ± 0.33%, 1.24 ± 0.27%, 650.03 ± 77.60 mg kg^-1 and 504.88 ± 18.53 mg kg^-1, respectively. In the case of copper, the magnetic fraction had a content of 11.27 ± 1.41%, corresponding to about 50% of the value obtained in the non-magnetic fraction. Hence, iron, nickel, silver and gold were concentrated in the magnetic fraction, while copper was concentrated in the non-magnetic fraction.

Keywords:
printed circuit boards; recycling; mechanical processing; characterization; metallic materials