Fast copper extraction from printed circuit boards using supercritical carbon dioxide

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Electrical and electronic equipment (EEE) demand is rising, leading to significant waste printed circuit boards (PCBs).
• PCBs contain valuable metals, notably copper (Cu), necessitating efficient recycling methods.
• Current recycling processes face challenges in speed and efficiency.

Purpose of the Study:

• To develop an innovative and efficient method for recovering copper (Cu) from waste mobile phone PCBs.
• To investigate the reaction kinetics of copper (Cu) leaching using supercritical CO2 with co-solvents.
• To establish a faster and environmentally acceptable recycling process for PCBs.

Main Methods:

• Characterization of waste mobile phone PCBs.
• Leaching experiments at atmospheric pressure and using supercritical CO2 with hydrogen peroxide (H2O2) and sulfuric acid (H2SO4) as co-solvents.
• Evaluation of reaction kinetics and copper (Cu) extraction efficiency.

Main Results:

• Waste PCBs were found to contain 34.83 wt% copper (Cu).
• Supercritical CO2 extraction demonstrated a 9-fold increase in speed compared to atmospheric pressure extraction.
• Approximately 90% of copper (Cu) was extracted within 20 minutes using supercritical leaching with 20% H2O2 and H2SO4 (2.5 M).

Conclusions:

• Supercritical CO2 leaching is a highly efficient method for recovering copper (Cu) from waste PCBs.
• The developed process offers significantly faster reaction kinetics, making PCB recycling more viable.
• Supercritical CO2 is an environmentally acceptable and reusable solvent, positioning it as a promising alternative for sustainable e-waste management.