Recycling of printed circuit boards: ultrasound-assisted comminution and leaching for metals recovery

The increase of electronic equipment consumption associated makes the recycling process crucial worldwide. Use of emerging technologies for recycling has demonstrated enhance process efficiency. Ultrasound-assisted in the comminution and leaching has been explored and results demonstrate the feasibility for e-waste applications. Thus, the present study aimed to evaluate the ultrasound on recycling of PCBs. Ultrasound-assisted comminution was applied to understand its effect on the leaching in different particle sizes. Results have shown that the particle size distribution of PCBs reduced by 25% in 4 h by ultrasound (700 W). The effect of acid concentration, solid-liquid ratio, ultrasound power, and oxidizing agent were explored in leaching experiments. Extraction of aluminum increased twice under the effect of ultrasound. The leaching efficiency for iron achieved a half compared with silent experiments due to the iron oxide formation resulting in less contaminant to the leach solution. It may cause lower nickel recovery. Leaching of copper was benefited by ultrasound under oxidant media.

Automated summary

The increase in electronic equipment consumption has made recycling processes crucial worldwide. The use of ultrasound technology in the recycling process has shown to enhance efficiency, particularly in the recycling of PCBs. The study found that ultrasound-assisted comminution reduced the particle size distribution of PCBs by 25% in 4 hours. Additionally, the leaching experiments showed that the extraction of aluminum doubled under the effect of ultrasound, while the leaching efficiency for iron decreased by half due to the formation of iron oxide, resulting in lower nickel recovery.