Recycle Week 2021
On average, one ton of gold ore contains up to five grams of pure gold. In comparison, one ton of discarded mobile phones can easily contain up to 300 grams of gold. Which means that mining gold from e-scrap would yield a better profit than from ore. In fact, according to Professor Jason Love, who is leading a team of researchers at the University of Edinburgh in developing a new compound to extract gold from used electronics, around seven percent of the world’s gold is inside electronic scrap, of which less than one-third is currently salvaged.
The research team effectively recovers ‘a very high purity of gold’ from various types of discarded electronics. First, the researchers place the printed circuit boards in a mild acid solution to dissolve any remaining metallic parts. Then, an oily liquid containing the new reagent is then added, which allows gold to be extracted selectively from the complex mixture of metals found inside electronics.
Professor Love explains that, normally, one molecule of reagent binds directly to a metal molecule. The innovative compound uses a different type of chemistry and can bind to clusters of gold molecules instead of just one. ‘This means you can use a lot less of it to recover the same amount of gold,’ he says.
Looking ahead, the scientists want to recover other valuable e-scrap metals including palladium, platinum, and neodymium. New reagents could be developed to salvage these, as well as common metals such as copper and tin. Love believes there may also be the opportunity to extract toxic metals such as cadmium and lead.
The Scottish experts are also interested in seeing how chemistry could be used to recover plastics from the growing mobile phone waste stream.
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