- Title: Golden opportunity for mobile metal extraction
- Date: 12th October 2016
- Summary: BARCELONA, SPAIN (FILE) (REUTERS) VARIOUS PEOPLE USING CELL PHONES TAIPEI, TAIWAN (FILE) (REUTERS) VARIOUS DUMPED MOBILE PHONES
- Embargoed: 27th October 2016 10:32
- Keywords: gold goldmine mine extraction electronics cellphone Edinburgh Jason Love
- Location: EDINBURGH, SCOTLAND, UK / FILE LOCATIONS
- City: EDINBURGH, SCOTLAND, UK / FILE LOCATIONS
- Country: United Kingdom
- Topics: Science
- Reuters ID: LVA00153P8XGB
- Aspect Ratio: 16:9
- Story Text: Scottish researchers have devised a simple chemical method for extracting gold from old mobile phones. Their findings could help clean up the often dangerous methods used to remove the precious metal from electrical waste, such as old cellphones, televisions and computers.
Up to seven percent of the world's gold is believed to be abandoned in unwanted electronics, the metal's conductive capacity making it a crucial part of circuit boards found inside electrical devices.
As well as being often inefficient, current extraction methods are also hazardous to health, using toxic chemicals such as cyanide to separate gold from other metals, after devices have been dissolved.
Professor Jason Love, of the University of Edinburgh's School of Chemistry, led the study. He told Reuters: "If you dissolved a mobile phone and then used these commercial re-agents to extract the metals or extract the gold you'd extract a lot of other metal as well."
By unravelling the chemistry behind the extraction process, the team formulated a new compound in the laboratory that effectively did the job, without using toxic chemicals.
"We're using a new re-agent which is extremely selective for gold, which is much better than other re-agents," he said. "That means there's much less waste, we should be able to fit this into a process, either used by the mining industry or used by people who look into recycling waste electronics."
The first part of the process is to place printed circuit boards into a mild acid, which dissolves all their metal parts. An oily liquid containing the special compound is then added, which extracts gold selectively from the mixture of metals.
Love talked Reuters through the process. He said: "We have our nice white compound dissolved in that organic solvent and then you can mix that organic solvent with the metals that you dissolve in water or in acid. When you mix them together you get two layers. Then if you give them a good shake you actually extract all of the gold that you have dissolved in this mixture of mobile phone metals and that goes then into this layer here. So it's a very simple but very selective compound for the extraction of gold from a mixture of metals you find in a mobile phone."
Love says that around 300 tonnes of gold are used in electronics every year, and that figure is likely to rise.
"Something like seven percent of gold that's used in the world at the moment is found in waste electronics. There's more and more electronics being used and developed - everybody wants their latest iPhone or something like this, and so you can see this is an expanding business, and rather than put this into landfill you're much better off trying to recycle these metals, especially gold, which is the most valuable metal in a mobile phone," he said.
Introducing a safer way to recover precious metal from discarded electronic devices could help reduce the negative environmental impact of gold mining and cut carbon dioxide emissions, Love believes. The technology could also be developed to extract other metals.
The study was funded by the Engineering and Physical Sciences Research Council and published in the journal Angewandte Chemie in August.
Love's team is in discussions with four commercial companies about scaling up the technique commercially.
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