Scientists at the University of Edinburgh in Scotland have come up with a simple and effective method for extracting gold from used electronics, a result which could help salvage some of the estimated 300 tonnes of gold used each year in electronics such as cellphones, computers and televisions, much of which currently ends up in landfills.
The numbers are staggering -worldwide, 50-million tonnes of e-waste from computers, cellphones and appliances are produced each year, an amount that has doubled just over the past five years. Reports show that much of the e-waste ends up in developing regions of Asia and Africa where regulations for the proper disposal and recycling of e-waste are less stringent, creating a one-way flow of potentially toxic materials from the West to the East.
E-waste contains both precious metals such as gold, copper, platinum and silver as well as many harmful substances like lead, mercury, cadmium and arsenic. The US Environmental Protection Agency says a million used cellphones contains upwards of 16,000 kg of copper, 350 kg of silver, 15 kg of palladium and 34 kg of gold. E-waste alone is said to contain up to seven per cent of the world’s gold.
But up until now, the process of extracting gold from used electronics, like computer circuit boards has been both inefficient and toxic, often requiring the use of hazardous chemicals like cyanide. The newly developed process involves a mild acid to dissolve the metal parts of printed circuit boards down to an oily liquid, followed by the addition of a chemical compound created by the research team which separates out the gold from the other metals.
“We are very excited about this discovery,” says Jason Love of the University of Edinburgh’s School of Chemistry and co-author of the study. “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 United Nations reports that the e-waste represents more than $52 billion yearly in potentially reusable resources, with less than one sixth of it having been properly recycled or reused. Canada alone produces over 860,000 tonnes of e-waste per year – about 24 kg per person. Experts writing in a recent commentary in the science journal Nature argued that international cooperation is required to stem the flow of used electronics to the poorer nations of the world and prevent further contamination of lands, people and ecosystems of the developing world.
The authors point to e-waste processing towns such as Guiyu, China, where lead levels in sampled blood from children have been found to be on average three times the safe limit.
“Researchers and regulators should build a global e-waste flow system that covers the whole life cycle of electrical goods, including production, usage, disposal, recovery and remanufacturing,” say the commentary’s authors. “Beyond better recycling, the ultimate aim should be a circular economy of cleaner production and less wasteful consumption, including the embrace of a sharing economy and cloud-based technologies with smaller material footprints.”
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