University of Edinburgh researchers have developed a novel method for extracting precious metals, including gold, from mobile devices and other electronic gadgets. The process is novel not only in its efficiency but also in its avoidance of any environmentally-damaging toxic chemicals. Many gold extraction processes are reliant upon the use of cyanide.
Gold cyanidation is a metallurgical technique for extracting gold from low-grade ore by converting the gold to a water-soluble coordination complex. The process is controversial, not least because cyanide spills can have a devastating effect on rivers, sometimes killing everything for several miles downstream.
With the new method, circuit boards are immersed in a mild acid which dissolves their metal parts. Following this, an oily liquid, containing a bespoke compound, is then added. This secondary process extracts the gold away from other metals, facilitating its collection and making it available for alternative uses.
In a research note, the lead scientist 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.”
The process could also be lucrative for, as the BBC notes, up to seven percent of the world’s gold is thought to be in electronic devices. The new method would allow for around 300 tonnes of gold to be extracted from electronic circuitry each year.
The process is described in the journal Angewandte Chemie, in a paper headed “.Gold from Waste: Selective recovery of gold from secondary resources by a simple extraction method”
