Supercritical extraction of polymers from printed circuit boards using CO2 and ethanol

The printed circuit boards are the fundamental components of waste electrical and electronic equipment (WEEE). The PCBs stand out due to the amount of metals in their composition as well for their complex and heterogeneous constitution that make their recycling difficult. In this context, the aims of the study was to evaluate the application of supercritical CO2 modified with ethanol in order to remove the polymers contained in PCBs from discarded mobile phones. The PCBs were characterized and an evaluation of the supercritical extraction was performed through experimental design. The characterization showed that PCBs contained 64.02 wt% of metals, 20.51 wt% of ceramics and 15.47 wt% of polymers. The fractional factorial experimental design showed that 69.53 wt% of the polymers present in the PCBs were extracted, at 170 °C and 7.5 MPa. As the remaining polymers are no longer covering the metals, they could be more easily leached and therefore more effectively recovered.