February 6, 2011

The "Endangered Element" Periodic Table

From Chemistry World:
'The periodic table is a thing of real beauty to chemists but we are staring at the possibility of not being able to access parts of it,' says Mike Pitts, of the UK's Chemistry Innovation Knowledge Transfer Network.

Pitts and his colleagues have compiled an 'endangered element' periodic table where red elements are under 'serious threat' of becoming unavailable in less than a century. Helium is marked red, as are the semiconductor staples gallium and indium. Meanwhile, the rare earth metals rank near the top of most 'critical' lists. 

Last October, China started building the world's biggest off-shore wind farm in Bohai Bay, a few hours from Beijing. The country is constructing wind farms on an unprecedented scale - surely good news given its insatiable appetite for coal. But each megawatt of power a wind turbine generates requires up to one tonne of rare earth permanent magnets. The elements used in the magnets - neodymium, dysprosium and terbium - are in short supply and the west is in danger of losing access to them as China's domestic needs soar.
Unfortunately, the green future of the UK and much of Europe also relies heavily on wind turbines rich in rare earths. And it's not just green technology that is under threat - many of our everyday electronic items, from iPhones to LCD televisions, depend on the same critical elements. . . .

Western governments are awakening slowly to the threat of losing access to key elements and expert panels in the EU and US have published lengthy reports. Critical raw materials for the EU, published in 2010, identified 14 raw materials and metal groups, including all of the rare earth and platinum group metals, as well as antimony, beryllium, cobalt, fluorspar, gallium, germanium, graphite, indium, magnesium, niobium, tantalum, and tungsten. The expert group that compiled the report would like to see 'policy actions' to make recycling more efficient and is keen to promote research into recycling 'technically challenging' products.

There's currently an imbalance between the rate at which we're using materials and recycling,' says Pitts. 'We are making the elements economically unrecoverable. You get concentrations of metals in waste streams that are higher than the ores they are coming from.'

The rare earth elements (REEs) - the fifteen lanthanides, plus scandium and yttrium - are being consumed at alarming rates, partly to feed our obsession with the latest must-have technology. 'The real gift of the rare earths has been miniaturisation,' says Jack Lifton, who runs a US consultancy called Technology Metals Research. Rare earths like neodymium and dysprosium are used to make small, lightweight, and incredibly strong magnets. From military high-tech gadgets to headphones, magnetic jewellery clasps and magnetic toys, the rare earths have brought huge benefits.

Many green technologies are heavily dependent on the REEs, especially wind turbines and hybrid cars; each Toyota Prius hybrid car is reported to contain as much as 1kg of neodymium in its motor and 10-15kg of lanthanum in its battery.

Although the metals are not all that rare, they are only found - lumped together - in particular regions of the Earth's crust. Their similar chemical properties make them difficult and expensive to separate from one another. Not only are they becoming harder to mine but the few nations that do mine them are clutching their precious resources ever tighter.

China has 37 per cent of the world's accessible reserves, according to the British Geological Survey (BGS), followed by the former Soviet Republics that make up the Commonwealth of Independent States, then the US and Australia. But China supplies about 96 per cent of the world's REEs, according to the BGS. In recent years it has started to cut rare earth exports and is expected to limit exports to finished products, according to the US Government Accountability Office (GAO).

Lifton is alarmed by the slow pace with which western governments are dealing with the supply situation. 'These metals are not used for their structural value - they are used for their unique electrical and magnetic properties and there is no substitute for them,' he says.

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