Researchers at the University of Cagliari in Italy and Imperial College London developed a method for extracting gold from printed circuit boards, SIM cards and other electronic waste, as well as a process for using the recovered gold in drug manufacturing.
In a paper published in the journal ACS Sustainable Chemistry & Engineering, the scientists explain that the extraction method involves selective steps for the sustainable leaching and recovery of base metals like nickel, then copper, silver and, finally, gold, using green and safe reagents.
The gold produced from this process, however, is part of a molecular compound and cannot be reused for electronics without investing a lot more energy to obtain the yellow metal.
Seeking a use for this compound of recovered gold, the research team investigated whether it could be applied as a catalyst in the manufacture of other materials or substances, including pharmaceuticals such as anti-inflammatory and pain-relief drugs.
They found that the gold compound performed as well, or better, than the currently used catalysts, and is also reusable, further improving its sustainability.
The scientists, thus, suggest that making it economically viable to recover gold from electronic waste could create spin-off uses for other components recovered in the process. For example, when applying the new technique, copper and nickel are also separated, as is the plastic itself, with all these components potentially being used in new products.
“By weight, a computer contains far more precious metals than mined ore, providing a concentrated source of these metals in an ‘urban mine’,” Sean McCarthy, the Ph.D. student leading the research in the lab at Imperial, said in a media statement.
Given the encouraging results, McCarthy and his colleagues are now working to extend this approach to the recovery and re-use of the palladium content of end-of-life automotive catalytic converters. This is particularly pressing as palladium is widely used in catalysis and is more expensive than gold. – (mining.com)