A research team from Edinburgh University believes the new technique could help safely rescue hundreds of tonnes of the precious metal from electronic scrap.
Electrical waste from items such as old mobile phones, televisions and computers, is thought to contain as much as seven per cent of all the world’s gold. The precious metal is a key component of the printed circuit boards found inside electrical devices.
Current ways of extracting gold from unused gadgets often use toxic chemicals such as cyanide, which can be hazardous to health.
Improving how the gold is recovered from discarded electronic devices could help reduce the environmental impact of gold mining and cut carbon dioxide emissions, the team says.
The Scottish team of scientists has now developed a simple extraction method using a non-toxic chemical compound, which they claim yields more efficient results.
The technique involves putting printed circuit boards in a mild acid, which dissolves all of their metal parts.
An oily liquid containing the team’s chemical compound is then added, which they have found is able to extracts gold.
The compound isolates gold from the complex mixture of other metals, enabling it to be extracted.
Study leader Professor Jason Love, of the university’s School of Chemistry, 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.”
The research team believes their discovery could help salvage some of the estimated 300 tonnes of gold used in electronics each year.
The study, published in the journal Angewandte Chemie, was funded by the Engineering and Physical Sciences Research Council. It is one of a number of initiatives at the university to promote the so-called circular economy, which encourages reuse of materials and greater resource efficiency.
There are 0.034 grams of gold in the average current day mobile phone, according to the US Geological Survey. There are also 16 grams of copper, 0.35 grams of silver,and 0.00034 grams of platinum.