Sadahiko Yokoyama

Recycling system for printed wiring boards with mounted parts

A practical recycling system has been developed for printed wiring boards (PWBs) with electronic parts mounted on them. This system consists of part-removing, solder-removing and resin-board pulverizing/separating processes, and is effective in the recovery of useful materials. The authors have developed a part-removal apparatus which successfully removes through-hole devices as well as surface mounted devices from PWBs with almost no damage to the devices themselves. Most of the solder is removed by the part-removal, and later by surface abrasion followed by heat/impact. After the removal of parts and solder, the resin-boards are pulverized and the resulting powder is then separated into two types: a copper-rich powder and a powder which consists of glass fiber and resin (GR powder). The copper-rich powder is a good copper resource for refining; the GR powder is usable as a filler for polymer products. Recovered parts which contains valuable metal resources (including gold), can be refined out, as is most commonly the case in other recycling systems, but a more economic and ecologically sound approach would be to exploit the potential of parts removed in this system to be reused for their original purposes after being checked for reliability.

Recycling of printed wiring board waste

We have developed a new material recycling process for printed wiring board (PWB) wastes. The main characteristics of the process are pulverizing the PWB wastes under 1 millimeter effectively, and separating copper rich powder from glass fiber and resin powder gravitationally. Copper recovery is up to 97 wt %. The residual glass fiber and resin powder is recyclable as a filler for resin construction materials. With the process, the PWB wastes can be reduced and utilized for valuable resources.<<ETX>>