Scientists from the University of Edinburgh in Scotland have developed a new method of extracting gold from disused electronic devices such as mobile phones, televisions and computers without using toxic chemicals.

This extraction process is expected to help recover approximately 300t of the precious metal.

According to researchers, existing methods for extracting gold are inefficient and can be dangerous to health, as they use toxic chemicals such as cyanide.

Electrical waste is believed to contain as much as 7% of the entire world’s gold.

"Electrical waste is believed to contain as much as 7% of the entire world’s gold."

Researchers noted that improving the way precious metal is recovered from discarded electronic devices is set to help minimise the environmental impact of gold mining, in addition to cutting carbon dioxide emissions.

The university team unravelled the complex chemistry underpinning the extraction process and discovered a compound that could be used to recover gold.

Gold can be extracted by placing the printed circuit boards in a mild acid, which dissolves all of their metal parts. An oily liquid containing the chemical compound is later added to extract the metal.

The latest findings may also facilitate the development of methods for large-scale recovery of gold and other precious metals from electronics waste.

Funded by the Engineering and Physical Sciences Research Council, the study is part of the university’s proposal to make a sustainable and socially responsible contribution to Scotland and the wider world.  

University of Edinburgh School of Chemistry 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.”