Review of printed circuit board recycling processes

T. Nakamura , M. Maeda

Waste printed circuit boards (PCBs) comprise a major part of electronic-scrap. The boards serve as a good resource for non-ferrous metals such as copper and precious metals. PCBs are traded worldwide.

However, despite the fact that PCBs contain valuable metals, they also contain harmful elements such as lead and antimony. Most PCBs are composed of epoxy and contain brominated flame retardants. Therefore, PCBs require specialized treatment in environment treatment processes.

A number of processes exist for PCB treatment. The main PCB recyclers that recover valuable metals include the non-ferrous metal smelters in Europe and Asia. One typical treatment process includes the Top Submerged Lancing furnace method. This process appears very simple, but its operation is not easy if many types of electronic-scrap wastes are required to be treated simultaneously.

Other typical processes include the combination of a pre-treatment furnace and copper smelting. A key technology is the removal of halogen elements from PCBs. Characteristics of several processes were reviewed from an economic and environmental perspective, and the behaviour of halogens in the processes was studied. Future PCB treatment trends will be discussed.