In this study, we cooperated with UWin Nanotech Co., Ltd. to recycle and refine the copper from the waste printed circuit board (PCB). The series processes including crushing, separation, dissolution, and reduction were used to recover the copper. However, the waste liquid will be generated in the process as well as the high concentration of nitrogen oxide (NOx) emissions. Therefore, we used a high-gravity rotating packed bed (HiGee RPB) to reduce the NOx emissions from the copper dissolution process. The waste liquid was treated by vacuum distillation before discharge. Compared with the traditional packed tower, the HiGee RPB can eliminate the mass transfer limitation between gas and liquid, thereby improving the mass transfer efficiency the absorption effect of NOx. The objectives of this study are to establish an integrated process for copper recovery from the waste PCB, to evaluate the effect of reduction and recovery of copper nitrate solution, to recover the waste liquid after reduction by vacuum distillation, and to evaluate the NOx removal via a HiGee RPB. The results indicated that the sieve analysis after the crushing and separation of the waste PCB with the particle size distribution greater than 150um accounted for 87.8% of the total weight. The board fragments had a copper content of 572 g/kg that compared to original copper content of 491 g/Kg. It was increased by 16%. The copper recovery results from the reduction method showed that when the iron powder input was increased to 1:2, the copper concentration of the reduced nitric acid aqueous solution was 0.375 g/L, and the copper reduction rate was increased to 99.75%. In addition, the waste liquid after reduction of copper nitrate was treated by vacuum distillation. After vacuum distillation, the amount of waste liquid can be reduced by 70%. For the removal of NOx, each batch of 2.5 g of copper chips and 40 mL of nitric acid (concentration of about 9M) was conducted, resulting in the maximum NOx concentration is 2200 ppm. The ratio of NO and NO2 is about 0.8. We used hydrogen peroxide, chlorine dioxide solution and ozone as oxidants, which the NOx removal efficiency of 86% by ozone can be achieved.

Copper recycle and refining, High-gravity rotating packed bed, Nitrogen oxide reduction