A study by a team of University of Edinburgh scientists has shown that vast quantities of gold could be salvaged from old mobile phones and other electronic goods using a non-toxic chemical compound.

Electrical waste — including old mobile phones, televisions and computers — is thought to contain as much as 7% of all the world’s gold.

Gold is a key component of the printed circuit boards inside devices.

The university team said existing methods for extracting gold from old gadgets can be inefficient and can be hazardous to health, as they often use toxic chemicals such as cyanide.

The Edinburgh scientists said they developed an extraction method that does not use toxic chemicals and recovers gold more effectively.

The breakthrough could help salvage some of the estimated 300 tonnes of gold used in electronics each year.

The new process involves putting printed circuit boards in a mild acid which dissolves all metal parts.

An oily liquid containing the team’s chemical compound is then added which extracts gold selectively from the other metals.

The findings could lead to large scale recovery of gold and other precious metals from waste electronics.

The Edinburgh study is published in the journal Angewandte Chemie and was funded by the Engineering and Physical Sciences Research Council.

“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,” said Prof. Jason Love of the School of Chemistry at the University of Edinburgh.