A new method safely extracts valuable metals locked up in discarded electronics and low-grade ore using dramatically less energy and fewer chemical materials than current methods, report University of Illinois Urbana-Champaign researchers in the journal Nature Chemical Engineering.
Gold and platinum group metals such as palladium, platinum and iridium are in high demand for use in electronics. However, sourcing these metals from mining and current electronics recycling techniques is not sustainable and comes with a high carbon footprint. Gold used in electronics accounts for 8% of the metal’s overall demand, and 90% of the gold used in electronics ends up in U.S. landfills yearly, the study reports.
The study, led by chemical and biomolecular engineering professor Xiao Su, describes the first precious metal extraction and separation process fully powered by the inherent energy of electrochemical liquid-liquid extraction, or e-LLE. The method uses a reduction-oxidation reaction to selectively extract gold and platinum group metal ions from a liquid containing dissolved electronic waste.