20/10/2016
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 workers and
children are reported to be used to break apart these
electronics, often using dangerous chemicals to get to the
valuable components. One town in south-eastern China called
Guiyu has claimed the dubious distinction of being the largest
e-waste site in the world. It’s causing terrible health
problems for its residents and polluting the soil, rivers and air
with mercury, arsenic, chromium and lead.
Even e-waste that is recycled in its country of origin poses a
challenge. In Australia, for example, recycling of e-waste still
involves industrial smelting which is high cost and far from
environmentally-benign.
THERE MUST BE A BETTER WAY?
Of course there is. Ideally, we’d stop changing our
smartphones faster than we change our underpants. But
recognising that changing consumer behaviour is probably the
least viable option, we need to come up with something
better.
Materials scientist Veena Sahajwalla from the University of
New South Wales is taking a small-scale approach to a global
problem. Sahajwalla, who will be presenting at BBC
Future’s WCIS event in November, sees the future in
“micro-factories”, one in every community, that can safely,
cleanly and efficiently extract all the valuable metals from
obsolete mobile phones and incinerate the rest.
Her approach is very hands-off, minimising the need for
human contact with the more dangerous materials inside
smartphones. The mobile phone is smashed apart using high-
voltage current. Then the valuable printed circuit boards are
retrieved by a robotic arm, and fed into a tiny furnace that
uses precisely-controlled, high-temperature reactions to draw
out the valuable metal alloys. Any toxic or unwanted
materials can then be safely incinerated.
The whole set-up is contained in something the size of a
shipping container, which could make it the ultimate cottage
industry for someone looking for gold in them thar mountains
of e-waste. Who knows – do it for long enough and you might
well be able to build your own solid-gold, diamond encrusted
smartphone.
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