VATIS UPDATE Article

Stephen Foley and his research team from the University of Saskatchewan, Canada, have developed a simple, cheap and environmentally benign solution that extracts gold in seconds, and can be recycled and reused. “We use one of the most mass-produced chemicals: acetic acid; at five per cent concentration it’s plain table vinegar. We use a minute amount of an acid and an oxidant to finish our solution,” said Foley. The solution is the greenest solvent next to water, so eliminates the vast number of environmental concerns that come with long standing methods of gold extraction.

In this technique, the gold extraction is done under very mild conditions while the solution dissolves gold with the fastest rate ever recorded. “Gold is stripped out from circuits in about 10 seconds leaving the other metals intact” Foley said. When time is factored in with lower toxicity and consequential effects, this new solution appears to be a natural replacement that could revolutionize the industry.

To highlight the improvement Foley’s solution presents, consider that it costs $1,520 to extract one kilogram of gold using aqua regia and results in 5,000 litres of waste. With the U of S solution it costs $66 to produce one kilogram of gold and results in 100 litres of waste that can be reused over again. The other main advantage over current recycling processes, he continued, is that this specific solution is gold selective, meaning it only dissolves gold not other base metals, like copper, nickel, iron and cobalt, found in printed circuit boards.