IMPACT | 18 October 2016

A diamond-encrusted iPhone can set you back $95m – but if this piece of i-bling is a little out of your price range, don’t feel despondent. Every smartphone contains precious metals including gold, silver, copper, platinum and palladium.

This is more than just an amusing detail about the device that never leaves your side. These precious metals are now looking more precious than ever, as we face the prospect of one day being no longer able to afford to dig them out of the ground. Suddenly your smartphone is looking a lot more valuable than you might think.

The hidden value of the metals inside our old electronics, and how we might best extract those materials is one of the topics that will be discussed at BBC Future’s World Changing Ideas Summit in Sydney in November.

WHAT EXACTLY IS IN MY SMARTPHONE?

Smartphones are pocket-sized vaults of precious metals and rare earths. A typical iPhone is estimated to house around 0.034g of gold, 0.34g of silver, 0.015g of palladium and less than one-thousandth of a gram of platinum. It also contains the less valuable but still significant aluminium (25g) and copper (around 15g).

One tonne of iPhones would deliver 300 times more gold than a tonne of gold ore and 6.5 times more silver than a tonne of silver ore

And that’s just the start. Smartphones also contain a range of rare earth elements – elements that are actually plentiful in the Earth’s crust but extremely difficult to mine and extract economically – including yttrium, lanthanum, terbium, neodymium, gadolinium and praseodymium.

Then there’s also the plastic, the glass, the battery… it’s a very long list of ingredients.

These are all present in relatively small amounts. But more than two billion people currently have a smartphone, and that number is projected to increase. What’s more, the concentration of some of these elements, such as gold and silver in a mobile phone is actually much higher than their concentration in an equivalent weight of ore. One tonne of iPhones would deliver 300 times more gold than a tonne of gold ore and 6.5 times more silver than a tonne of silver ore.

WHY IS THIS A PROBLEM?

Because those two billion smartphone users upgrade to a new phone roughly every 11 months, which means their old smartphone gets cast into a drawer somewhere and forgotten about, or it gets thrown out. Barely 10% of these get recycled and their precious components recovered and reused. It’s a veritable goldmine sitting in cupboards, in boxes, in landfill. In an era when the prefix ‘peak’ is starting to be added to a whole lot of resources as well as oil, it makes economic and environmental sense to avoiding wasting such valuable substances.

WHAT HAPPENS TO THESE RESOURCES WHEN A SMARTPHONE BECOMES OBSOLETE?

In case you’re thinking of trying a little electronic gold mining at the individual scale, the miniscule amounts in each smartphone should make you think twice. But once you start thinking at the big scale, it looks a lot more attractive: one million mobile phones could deliver nearly 16 tonnes of copper, 350kg of silver, 34kg of gold and 15kg of palladium.

The challenge is how to recover those minerals and materials safely and economically. A significant proportion of e-waste – including mobile phones – gets exported or dumped in countries such as China where poorly paid

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