Separation process of plastic and metal from CD-R using pulsed power

The authors are investigating a new recycling method for metal and plastic from metal-coated plastics used as components of automobiles and electronics. A CD-R was used as an example of our work, with the separation by pulsed power of metal (silver layer) and plastic (polycarbonate substrate) from the CD-R investigated. The pulsed power from a magnetic pulse compression generator with a maximum storage energy of 40 J/pulse was applied to the gap between two ring electrodes placed on the CD-R. The progress of the removal of silver layer was observed at each pulsed voltage application. Results showed almost complete separation of the silver layer from the polycarbonate substrate by 25 shots of pulsed power with a stored energy of 35.3 J/pulse. In addition, discharge state was observed at each shot using a spectroscope and camera. Light emission from discharge at the first shot revealed a spectrum related to silver, indicating that the insulation layers (protection layer and printed layer) were punctured and the discharge took place between the ring electrodes and silver layer. Subsequent shots, revealed one or two peaks in voltage waveform. After the 7
^th
or 8
^th
shot, the value of the first peak increased with shot number. As the number of shots increased, the silver layer around the ring electrode was gradually removed, and the gap length between the ring electrode and the exposed silver layer also gradually increased. Therefore, the value of the first peak after the 7
^th
or 8
^th
shot is supposed to correspond to the discharge onset voltage in the air gap between the ring electrodes via the exposed silver layer.