Simple method can extract gold from old phones

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London: Hundreds of tonnes of gold could be recovered from old electronic devices such as smartphones, TV sets and computers each year, thanks to a simple chemical method developed by researchers.

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

Electrical waste - including old mobile phones, televisions and computers - is thought to contain as much as seven per cent of all the world's gold, a key component of the printed circuit boards found inside electrical devices.

Improving how the precious metal is recovered from discarded electronic devices could help reduce the environmental impact of gold mining and cut carbon dioxide emissions, according to researchers from University of Edinburgh in the UK.

They 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, researchers said.

By unravelling the complex chemistry underpinning the extraction process, researchers discovered a compound that could be used to recover gold more effectively.

Printed circuit boards are first placed in a mild acid, which dissolves all of their metal parts. An oily liquid containing the chemical compound is then added, which extracts gold selectively from the complex mixture of other metals.

The findings could aid the development of methods for large-scale recovery of gold and other precious metals from waste electronics, researchers 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," said Jason Love from University of Edinburgh.

The findings were published in the journal Angewandte Chemie.