New gold standard for recycling WEEE

The precious metal is a key component of the printed circuit boards found inside these electrical devices, and as much as seven per cent of all the world’s gold is thought to be contained within them.

Current methods for extracting gold from old gadgets are inefficient and can be hazardous to health because they often use toxic chemicals such as cyanide, researchers say.

Now, Edinburgh scientists have developed a simple extraction method that does not use toxic chemicals and recovers gold more effectively than current methods. The finding could help salvage some of the estimated 300 tonnes of gold used in electronics each year.

To extract the gold, printed circuit boards are first placed in a mild acid, which dissolves all of their metal parts. An oily toluene solvent containing the team’s primary amide is then added, which extracts gold selectively from the mixture of other metals.