Based on the Environmental Protection Agency's sustainable development of innovative technology research and development program in 2013, we have successfully developed an environmental stripping technology to recover metal from waste printed circuit boards. This project is mainly to extend the research and development results, and further develop a pilot-scale production process to recover solder scrap from waste appliances, computer and mobile phone motherboards. The project is to remove and purify the solder metal used in the printed circuit board. Traditionally, the strong acid washing is commonly used for the recovery of precious metals on printed circuit boards. In this washing process, most of metal is stripped and the precious metals are further purified using a precipitation reaction. However, low-value metal waste and residual waste liquid are arbitrarily dumped or buried, resulting in serious environmental pollution. The present study develops an environmental stripping procedure to recover tin from the pins of printed circuit boards pins. The tin is finally purified using a suitable purification procedure, thus achieving the purpose of greed-recycling. This study also assessed the economic value of this recycling process, counseling waste board recycling companies to import this environmentally friendly stripping technology.

Discarded printed circuit boards, Tin, Recycling