Another iPad launch, another event filled with intense anticipation and speculation. This time Apple’s CEO Tim Cook revealed that the latest iteration of iPad will feature a high-definition screen, and no doubt its competitors will rapidly follow suit.
But there is a problem looming on the horizon for fans of the latest tablet computers, not to mention smart phones and flatscreen TVs. Whether it is on the shiny new iPad, computer or phone, the chances are that you are reading this article through a screen laced with one of the rarest metals on Earth: indium. And analysts are warning that global supplies of indium could be exhausted as soon as 2017. So how will we live without the gadgets that we have come to depend on?
Such a prospect might not seem as alarming as running out of essential commodities, such as food or water. But over the past few decades digital displays have become so enmeshed in our lives that they are integral to our social interactions and livelihoods from rural East Africa to the offices of Wall Street. I have met Kenyan fisherwomen trading their wares via SMS to clients based hundreds of kilometres away – an opportunity that depends on indium just as much as my need to read these words I am typing on my computer monitor.
Wonder metal
Though it was discovered 150 years ago, indium’s remarkable qualities have been harnessed only recently to create wafer-thin electrodes. It is a very soft silvery metal that can be painted onto glass because unlike other soft metals, such as mercury, it wets the glass rather than forming beads. (Another curious property of indium is that when you bend a rod of the metal, it issues a high-pitched crackling sound, known as its “cry”.)
Indium is most useful, however, when it is manufactured into indium tin oxide, or ITO. The reason you cannot see it is because when indium reacts with oxygen, it becomes transparent. This, plus its tremendous ability to conduct electricity, allows our mobile phones to be smarter, our TV flatscreens to be larger and our tablet computers to be more sleek.
As a result, the price of indium has rocketed in recent years – it went from $60 per kilogramme in 2003 to $1,000 in just three years – giving rise to a whole new indium smuggling industry, primarily out of China. And there is no let up on our demand for hi-tech displays – there were more than 1.5 billion mobile phone handsets alone sold in 2011, one of which was to me.
But the supply of indium cannot meet our voracious demands. Indium is harvested as a byproduct of zinc mining because this so-called "hitchhiker" metal exists almost entirely in trace amounts inside deposits of other ores such as zinc and lead – sometimes as little as 1 part per million. And because indium is not mined in its own right, greater demand for it won't necessarily lead to more being mined, according to Robert Ayres, a physicist and economist at INSEAD business school in France. "Most of the indium is just single atoms stuck inside rock that can never be utilised," he says.
If the most gloomy predictions for indium are true, Ayres says the only solution is to increase recycling efforts. Because of its value, the indium recycling market is already bigger than primary production.
But a single monitor screen typically contains less than 0.5 g of ITO, so recovering such a tiny amount from electronic products is expensive and energy-intensive. "I call indium a “spice metal”, because it's sprinkled into products in a way that makes it almost impossible to recover," says Armin Reller, a materials physicist at the University of Augsburg in Germany.
