Japanese R&D team pursues microwave effect for cables

Scientists from Sophia University and Università di Pavia in Tokyo have developed a microwave-induced pyrolysis method to recycle VVF power cables, which are made from copper and aluminium.

The novel method carbonises the PVC insulation and exposes the copper wire without damaging it. This allows for easy recovery without generating toxic by-products.

The breakthrough is thanks to a machine called the FlexiWave and details have been published in the journal RSC Advances. The recycling rate for PVC insulation material is currently only about 35%.

‘VVF cables have a high reuse value among end-of-life electronics,’ comments Satoshi Horikoshi, one of the study’s lead authors. ‘Our method is suitable for recycling and requires no pre-treatment to separate the plastics from the metals.’ The new approach also eliminates pre-cutting the cables.

Researchers placed VVF power cables containing two copper wires within PVC insulation into a glass reactor and exposed them to microwave radiation of 100W, 200W and 300W. Nitrogen gas was introduced into the reactor to prevent combustion. Different dimensions of cables were successfully recycled in under 12 minutes.

Horishoki adds that chlorine can be recycled as hydrochloric acid while the carbon and activated carbon produced can be recovered as carbon black. ‘We have created a new field of “microwave science”,’ he says proudly.