Saskatoon Scientists Pulling Gold Out of e-Waste


The world produces almost 50M tonnes of e-waste each year

Inside phones, computers, tablets and other electronics there is a little bit of gold in the circuit board, and a University of Saskatchewan chemistry professor has found a way to easily get it out.

Stephen Foley said the world produces almost 50 million tonnes of e-waste each year and most of it ends up in landfills. Only about 30 per cent is recycled, which means a lot of gold is going to waste.

“Anytime you look at a circuit board and you see… a ceramic with a green plastic coating and the metal that goes around the circuit board, all that metal is usually a layer of copper, over a layer of nickel, over a layer of gold,” Foley said.

“We use concentrated vinegar to selectively remove the gold.”

•E-waste worst offenders include U.S., China, says UN report

Currently, Foley said there are a few places that recycle circuit boards, but they usually only remove the nickel and copper. It’s not financially viable to remove the gold. But while his team at the lab was looking for a substance to selectively bind gold for other purposes, they stumbled upon a solution.

“They were investigating concentrated vinegar as a solvent, and they found that they could use this solvent, with a few minor additions of extra chemicals in there, to be a very efficient solvent for stripping gold off of circuit boards,” he said.

The gold comes out in an oxidized form solution, but the team added zinc which makes it a solid.

Foley said, for chemists, it’s actually quite a simple process and happens in seconds.

Using this new process, it would cost about $70 to strip enough circuit boards to get about one kilogram of gold, which Foley says would be worth $45,000.

With gold in their sights, Foley said they are looking to scale up.

“We are looking at companies that are already looking at recycling circuit boards or looking for investors to start up our own company to get this going,” he said.

Foley added the process is not for “in the garage,” it would need to be done on a larger scale to be worth it.

A UN study estimated e-waste dumped around the world in 2014 was worth $52 billion. That report said Canada dumped around 725,000 tonnes of the electronic waste

Source: CBC News

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