Non-Toxic Gold Extraction | Research at Curtin

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Most of the world’s gold is extracted from
ore using highly toxic re-agents. This ranges from large scale mining operations using cyanide
to artisinal miners who use large quantities of mercury as they can’t legally get a hold
of cyanide. We believe we’re to have come up with what
can potentially be the tipping point at which industry says make the switch. Cyanide is costly to make and has to be carefully
transported to the processing site and then just as carefully disposed of afterwards as
it can’t be reused. While alternatives to cyanide exist none are
truly benign as they’re often not biodegradable. In Curtin’s Department of Minerals Extraction
and Extractive Metallurgy engineers have developed a commercially viable alternative process.
It’s environmentally benign, safer, of comparable cost to cyanide technologies and allows at
site production. After nine months of development they’ve come
up with a re-agent mix, highly selective for precious metals. It dissolves copper at lower
temperatures and gold and silver at slightly elevated temperatures. While the reagent mix
works well for finely ground, free milling gold ores, it’s primary potential is as a
reagent for extracting gold from low grade deposits. This can be either in heaps or in-situ where
it’s environmentally benign nature poses less risk to ground water than cyanide. And there
are a number of additional benefits with global impact. It could be used to recover precious
metals from circuit boards and other electronic waste which might otherwise go to land fill. And in developing countries miners could easily
obtain the new reagent suite replacing the highly toxic mercury that they now use. Any industry seeks to keep it’s costs low
and mining is no exception. It’s hugely capital intensive because this new reagent uses similar
down stream processing as cyanide the costs associated with implementing the technology
are kept to a minimum. With our technology industry can reap the
benefits with out having to replace their existing plant. Our reagent is cleaner, safer, and presents
a new solution to a century old problem.

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