Endangered Elements Critical Thinking As Our Supply of Some Essential Elements Dries Up, It’S Time to Start Urban Mining
Total Page：16
File Type：pdf, Size：1020Kb
Endangered elements Critical thinking As our supply of some essential elements dries up, it’s time to start urban mining. Emma Davies reports Serious threat in the next 100 years Rising threat from increased use Limited availability, future risk to supply Source: Chemistry Innovation Knowledge Transfer Network ADAPTED FROM WWW.CHEMICAL INNOVATION.CO.UK WWW.CHEMICAL FROM ADAPTED 50 | Chemistry World | January 2011 www.chemistryworld.org Last October, China started Mike Pitts, of the UK’s Chemistry between the rate at which we’re In short building the world’s biggest off- Innovation Knowledge Transfer using materials and recycling,’ says shore wind farm in Bohai Bay, a few Network. Supply of several Pitts. ‘We are making the elements hours from Beijing. The country Pitts and his colleagues have elements, including economically unrecoverable. You is constructing wind farms on an compiled an ‘endangered element’ helium, phosphorus, get concentrations of metals in unprecedented scale – surely good periodic table where red elements indium and gallium is waste streams that are higher than news given its insatiable appetite are under ‘serious threat’ of predicted to exceed the ores they are coming from.’ for coal. But each megawatt of becoming unavailable in less demand in the near future power a wind turbine generates than a century (see facing page). Rare earths used in Magnetic attraction requires up to one tonne of rare Helium is marked red, as are the magnets and electronics The rare earth elements (REEs) earth permanent magnets. The semiconductor staples gallium and are not scarce, but are – the fifteen lanthanides, plus elements used in the magnets indium. Meanwhile, the rare earth difficult to separate and scandium and yttrium – are being – neodymium, dysprosium and metals rank near the top of most purify consumed at alarming rates, partly terbium – are in short supply and ‘critical’ lists. The west relies on to feed our obsession with the the west is in danger of losing China to supply rare latest must-have technology. ‘The access to them as China’s domestic Action stations earths, but as China’s real gift of the rare earths has been needs soar. Western governments are domestic demand miniaturisation,’ says Jack Lifton, Unfortunately, the green future awakening slowly to the threat of grows, alternatives are who runs a US consultancy called of the UK and much of Europe also losing access to key elements and desperately required. Technology Metals Research. relies heavily on wind turbines rich expert panels in the EU and US Recycling and Rare earths like neodymium and in rare earths. And it’s not just green have published lengthy reports. alternative sources are dysprosium are used to make small, technology that is under threat – Critical raw materials for the EU, being explored, but they lightweight, and incredibly strong many of our everyday electronic published in 2010, identified 14 may not arrive quickly magnets. From military high-tech items, from iPhones to LCD raw materials and metal groups, enough to plug the short gadgets to headphones, magnetic televisions, depend on the same including all of the rare earth and term demand gap jewellery clasps and magnetic toys, critical elements. platinum group metals, as well the rare earths have brought huge Rare earths are not the only as antimony, beryllium, cobalt, benefits. elements causing supply concerns fluorspar, gallium, germanium, Many green technologies are – elements such as helium (see graphite, indium, magnesium, heavily dependent on the REEs, Balloon about to burst? p53), niobium, tantalum, and tungsten. especially wind turbines and hybrid phosphorus (see Taking the P, p54) The expert group that compiled cars; each Toyota Prius hybrid car and copper are beginning to slip the report would like to see ‘policy is reported to contain as much as from our grasp. actions’ to make recycling more A monument in a field of 1kg of neodymium in its motor and ‘The periodic table is a thing efficient and is keen to promote wind turbines in Damao, 10–15kg of lanthanum in its battery. of real beauty to chemists but we research into recycling ‘technically China. The inscription Although the metals are not all are staring at the possibility of not challenging’ products. reads: ‘The home of rare that rare, they are only found – being able to access parts of it,’ says ‘There’s currently an imbalance earths welcomes you’ lumped together – in particular REUTERS www.chemistryworld.org Chemistry World | January 2011 | 51 Endangered elements The screen ‘Indium is one of the most critical elements cells and flat panel displays. ‘There is more indium and gallium in use because of the way that we use it,’ says Mike The Earth’s crust contains roughly three than in proven possible reserves,’ says Pitts, from the UK’s Chemistry Innovation times as much indium as silver, although silver Roger Morton from UK recycling specialists Knowledge Transfer Network. For example, can be mined far more efficiently. In 2007 the Axion Consulting. ‘So it’s more interesting to every liquid crystal display screen contains US Geological Survey estimated that we will mine stuff around you than mine it out of the indium components. run out of indium for extraction in less than two ground,’ he says. About 45 per cent of all indium extracted is decades, although the indium industry tends to Recycling the indium from spent technology used for the indium tin oxide that lines solar dispute such figures. holds an obvious appeal but industry is reluctant to invest. C-Tech innovation, a UK technology development company, was part of a recent project to recycle flat screens and THINKSTOCK recover liquid crystals, glass, and indium using an acid-leaching process. ‘We have the technology which will work to recover the indium from screens, but at the moment it’s not economically viable,’ says Ian Holmes, project manager at C-Tech. ‘The price of indium is less than half of what it was when we started the project three years ago,’ he says. The project highlighted several recycling issues, not least the differing internal makeup of seemingly identical devices. ‘There’s a long list of issues to be addressed,’ says Holmes. In the past couple of years, Axion has had interest from some major Asian electronics manufacturers looking to set up segregated EU recycling schemes for their branded products, says Morton. The idea is that the companies would stay in touch with those who had bought their technology and after a few years offer a deal on a new model in exchange for the old. Although such schemes would boost sales of new products, the ‘prime driver is to get the resource back,’ says Morton. ‘It’s much easier to recycle a stream of identical Apparently identical screens can be different inside, making recycling more difficult computers of a single brand.’ regions of the Earth’s crust. Their their unique electrical and magnetic similar chemical properties make properties and there is no substitute them difficult and expensive to for them,’ he says. separate from one another. Not only are they becoming harder to mine Heavy heart but the few nations that do mine Demand is predicted to outpace them are clutching their precious supply for the so-called heavy rare resources ever tighter. earths dysprosium and terbium in China has 37 per cent of the little more than a decade, perhaps world’s accessible reserves, less. Not only are the elements according to the British Geological harder to extract than the light Survey (BGS), followed by the REEs, but all of the world’s heavy former Soviet Republics that rare earths are mined in China. make up the Commonwealth of Dysprosium and terbium are Independent States, then the US ‘miracle ingredients of green and Australia. But China supplies energy products,’ says Lifton. Very about 96 per cent of the world’s small amounts of dysprosium give REEs, according to the BGS. In magnets that are up to 90 per cent recent years it has started to cut rare lighter, while terbium can cut the earth exports and is expected to electricity consumption of lights limit exports to finished products, by up to 80 per cent. Alloying according to the US Government neodymium with terbium and Accountability Office (GAO). dysprosium preserves the magnetic Lifton is alarmed by the slow pace properties at the high temperatures with which western governments of hybrid car engines and wind are dealing with the supply situation. turbines. The high temperature ‘These metals are not used for their magnets need considerably more ISTOCKPHOTOS structural value – they are used for dysprosium relative to neodymium 52 | Chemistry World | January 2011 www.chemistryworld.org Balloon about to burst? Helium may be the second most abundant element in the universe, but here on earth this noble gas is rare and precious. The only element to remain liquid at absolute zero, its two stable isotopes, helium-4 and helium-3, are essential and irreplaceable mainstays of cryogenics. 4He can supercool magnets down to about 1.8K, and 3He goes really low – down to below 1K. For years, US government stockpiles have created the illusion of an abundant supply of 4He and an adequate supply of 3He, but recently growing worldwide demand and short-sighted management have shattered the illusion. Global demand for 4He is climbing as emerging powers such as China and India step up helium-hungry activities.Yet, despite the small supply and the growing demand, helium is cheap – a helium filled party balloon costs just a few dollars, for example. This is because the US government, which controls the Fort Knox of helium – the US National Helium Reserve near Amarillo, Texas – has been selling it off at bargain basement prices.