Scientists claim to have developed a more effective method for extracting gold from printed circuit boards (PCBs) in old electrical items.
University of Edinburgh researchers have found a simple extraction method using a non-toxic compound that recovers gold more effectively than current methods.
Existing ways to remove gold are inefficient and can be hazardous to health because they often use toxic chemicals such as cyanide.
In the university’s method, PCBs are placed in a mild acid, which dissolves all metal parts. An oily liquid containing the new compound is then added, which extracts gold selectively from the complex mixture of other metals.
The researchers said the extraction method could help to cut the environmental impact of gold mining and reduce carbon dioxide emissions.
The work is part of a study by the university, published in the journal Angewandte Chemie and funded by the Engineering and Physical Sciences Research Council.
It estimates that PCBs inside mobile phones, televisions and computers contain as much as 7% of all the world’s gold, amounting to 300 tonnes.
Professor Jason Love said: “We are very excited about this discovery, especially as we have shown that our fundamental chemical studies on the recovery of valuable metals from electronic waste could have potential economic and societal benefits.”