Endangered Elements - Critical Thinking_tcm18-196054

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www.chemistryworld.org50 | Chemistry World | January 2011

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

ADAPTEDFROMWWW.CHEMICALINNOVATION.CO.UK

Source: Chemistry Innovation Knowledge Transfer Network



www.chemistryworld.org Chemistry World | January 2011 | 5

Last October, China startedbuilding the world’s biggest off-shore wind farm in Bohai Bay, a fewhours from Beijing. The countryis constructing wind farms on anunprecedented scale – surely goodnews given its insatiable appetitefor coal. But each megawatt of power a wind turbine generatesrequires up to one tonne of rareearth permanent magnets. Theelements used in the magnets– neodymium, dysprosium andterbium – are in short supply andthe west is in danger of losing access to them as China’s domesticneeds soar.

Unfortunately, the green futureof the UK and much of Europe alsorelies heavily on wind turbines richin rare earths. And it’s not just greentechnology that is under threat –many of our everyday electronicitems, from iPhones to LCD

televisions, depend on the samecritical elements.Rare earths are not the only

elements causing supply concerns– elements such as helium (seeBalloon about to burst? p53),phosphorus (see Taking the P, p54)and copper are beginning to slipfrom our grasp.

‘The periodic table is a thing of real beauty to chemists but weare staring at the possibility of notbeing able to access parts of it,’ says

Mike Pitts, of the UK’s ChemistryInnovation Knowledge TransferNetwork.

Pitts and his colleagues havecompiled an ‘endangered element’periodic table where red elementsare under ‘serious threat’ of becoming unavailable in lessthan a century (see facing page).Helium is marked red, as are thesemiconductor staples gallium andindium. Meanwhile, the rare earthmetals rank near the top of most‘critical’ lists.

Action stations

Western governments areawakening slowly to the threat of losing access to key elements andexpert panels in the EU and UShave published lengthy reports.Critical raw materials for the EU, published in 2010, identified 14raw materials and metal groups,

including all of the rare earth andplatinum group metals, as wellas antimony, beryllium, cobalt,fluorspar, gallium, germanium,graphite, indium, magnesium,niobium, tantalum, and tungsten.The expert group that compiledthe report would like to see ‘policyactions’ to make recycling moreefficient and is keen to promoteresearch into recycling ‘technicallychallenging’ products.

‘There’s currently an imbalance

between the rate at which we’reusing materials and recycling,’ saysPitts. ‘We are making the elementseconomically unrecoverable. Youget concentrations of metals inwaste streams that are higher thanthe ores they are coming from.’

Magnetic attraction

The rare earth elements (REEs)– the fifteen lanthanides, plusscandium and yttrium – are being consumed at alarming rates, partlyto feed our obsession with thelatest must-have technology. ‘Thereal gift of the rare earths has beenminiaturisation,’ says Jack Lifton,who runs a US consultancy calledTechnology Metals Research.Rare earths like neodymium anddysprosium are used to make small,lightweight, and incredibly strong magnets. From military high-techgadgets to headphones, magnetic

jewellery clasps and magnetic toys,the rare earths have brought hugebenefits.

Many green technologies areheavily dependent on the REEs,especially wind turbines and hybridcars; each Toyota Prius hybrid caris reported to contain as much as1kg of neodymium in its motor and10–15kg of lanthanum in its battery.

Although the metals are not allthat rare, they are only found –lumped together – in particular

In short

Supply of several

elements, including

helium, phosphorus,

indium and gallium is

predicted to exceed

demand in the near future

Rare earths used in

magnets and electronics

are not scarce, but are

difficult to separate and

purify

The west relies on

China to supply rare

earths, but as China’s

domestic demand

grows, alternatives are

desperately required.

Recycling and

alternative sources are

being explored, but they

may not arrive quickly

enough to plug the short

term demand gap

A monument in a field of

wind turbines in Damao,

China. The inscription

reads: ‘The home of rare

earths welcomes you’



52 | Chemistry World | January 2011

Endangered elements

regions of the Earth’s crust. Theirsimilar chemical properties makethem difficult and expensive toseparate from one another. Not onlyare they becoming harder to minebut the few nations that do minethem are clutching their preciousresources ever tighter.

China has 37 per cent of theworld’s accessible reserves,according to the British GeologicalSurvey (BGS), followed by theformer Soviet Republics thatmake up the Commonwealth of

Independent States, then the USand Australia. But China suppliesabout 96 per cent of the world’sREEs, according to the BGS. Inrecent years it has started to cut rareearth exports and is expected tolimit exports to finished products,according to the US GovernmentAccountability Office (GAO).

Lifton is alarmed by the slow pacewith which western governmentsare dealing with the supply situation.‘These metals are not used for theirstructural value – they are used for

The screen

‘Indium is one of the most critical elements

because of the way that we use it,’ says Mike

Pitts, from the UK’s Chemistry Innovation

Knowledge Transfer Network. For example,

every liquid crystal display screen contains

indium components.

About 45 per cent of all indium extracted is

used for the indium tin oxide that lines solar

cells and flat panel displays.The Earth’s crust contains roughly three

times as much indium as silver, although silvercan be mined far more efficiently. In 2007 theUS Geological Survey estimated that we willrun out of indium for extraction in less than twodecades, although the indium industry tends to

dispute such figures.

‘There is more indium and gallium in usethan in proven possible reserves,’ saysRoger Morton from UK recycling specialistsAxion Consulting. ‘So it’s more interesting tomine stuff around you than mine it out of theground,’ he says.

Recycling the indium from spent technology

holds an obvious appeal but industry isreluctant to invest. C-Tech innovation, a UKtechnology development company, was partof a recent project to recycle flat screens andrecover liquid crystals, glass, and indiumusing an acid-leaching process. ‘We havethe technology which will work to recover theindium from screens, but at the moment it’s noteconomically viable,’ says Ian Holmes, projectmanager at C-Tech. ‘The price of indium is lessthan half of what it was when we started theproject three years ago,’ he says. The projecthighlighted several recycling issues, not leastthe differing internal makeup of seeminglyidentical 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

computers of a single brand.’Apparently identical screens can be different inside, making recycling more difficult

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their unique electrical and magneticproperties and there is no substitutefor them,’ he says.

Heavy heart

Demand is predicted to outpacesupply for the so-called heavy rareearths dysprosium and terbium inlittle more than a decade, perhapsless. Not only are the elementsharder to extract than the lightREEs, but all of the world’s heavyrare earths are mined in China.

Dysprosium and terbium are

‘miracle ingredients of greenenergy products,’ says Lifton. Verysmall amounts of dysprosium givemagnets that are up to 90 per centlighter, while terbium can cut theelectricity consumption of lightsby up to 80 per cent. Alloying neodymium with terbium anddysprosium preserves the magneticproperties at the high temperaturesof hybrid car engines and windturbines. The high temperaturemagnets need considerably moredysprosium relative to neodymium I S

T O C K P H O T O S



Chemistry World | January 2011 | 53

its rare earth mine in southeastAlaska, which could producesignificant amounts of dysprosium.Canada has several mines underdevelopment. The problem with allof these is that the start-up costs arehigh but the mines are small, withlimited revenues, says Lifton. ‘Soeither you subsidise them or youget the end-user industry to put themoney in and develop them.’

Mountain Pass in California,US, was once the largest rare earthmine in the world – but ceased

production in 2002, partly becauseof Chinese businesses undercutting prices. Now US company Molycorpis set to reopen the mine in 2011,and by 2012 expects to be mining and separating cerium, lanthanum,praseodymium, and neodymiumoxides at full capacity. The minewill do much to ease the currentpressure on neodymium supplies.

Yet Mountain Pass will notinitially be able to refine the rareearth oxides into raw materials andwill probably have to ship themto China. Refined rare earths are

than is found in the ores.The Chinese think they are

running out of dysprosium andterbium, explains Lifton. Chinacurrently produces about 900tonnes of dysprosium per yearand estimates that it can minea further 13 500 tonnes. So atthe current consumption rate,the country could run out of theelement in 15 years. But given thesoaring demand, reserves could beexhausted even sooner.

‘If we want electric cars, we

had better start producing somedysprosium, because the Chinesewon’t keep supplying it to us,’ addsLifton. ‘My guess is we’re going to be short of dysprosium beforeanyone gets a solution rolling.’The US GAO has reported that itmay take up to 15 years to rebuild arare earth supply chain in the US.Industry is onto the problem buttime is running out.

Countries with reserves arescrambling to open mines. InJuly 2010 US company UcoreRare Metals started drilling at

Helium may be the second most abundantelement in the universe, but here on earththis noble gas is rare and precious. The onlyelement to remain liquid at absolute zero, itstwo stable isotopes, helium-4 and helium-3,are essential and irreplaceable mainstaysof cryogenics. 4He can supercool magnets

down to about 1.8K, and3

He goes really low –down to below 1K. For years, US governmentstockpiles have created the illusion of anabundant supply of 4He and an adequatesupply of 3He, but recently growing worldwidedemand and short-sighted management haveshattered the illusion.

Global demand for 4He is climbing asemerging powers such as China and India stepup helium-hungry activities.Yet, despite thesmall supply and the growing demand, heliumis cheap – a helium filled party balloon costs just a few dollars, for example. This is becausethe US government, which controls the FortKnox of helium – the US National Helium

Reserve near Amarillo, Texas – has beenselling it off at bargain basement prices.

The cheap price means that this preciousresource has been squandered, accordingto Nobel laureate Robert Richardson,who discovered liquid helium’s superfluidproperties. At the current rates, ‘the worldwould run out in 25 years, plus or minus fiveyears,’ he told a gathering of Nobel laureatesin August of this year.

4He can be recycled, but with prices so low,there is little incentive. The price needs torise by 20- to 50-fold to make recycling worthwhile, according to Richardson, who says that a

helium-filled balloon should cost $100. Spurredon by recent National Research Councilrecommendations to sell 4He at market prices,the US government announced in August thatprices will increase by 15 per cent in 2011.

3He is critical for European Organisation forNuclear Research (CERN) in Switzerland, andother neutron scattering facilities. The isotopehas also revolutionised lung imaging, andit is used in oil and gas exploration. 3He is abyproduct of the radioactive decay of tritium,

the heavy-hydrogen used in thermonuclearwarheads. Thanks to the cold war arms race,the US has had a steady and adequate supply.

But after the terrorist attacks on11 September 2001, US national securityagencies began using 3He in nuclear detectorsthat were installed by the thousands atairports, shipyards and border crossings.These scanners now account for 80 per centof US consumption of the gas.Rebecca Renner

Artificially cheap prices and poor resource management could spell the end of the party balloon

Balloon about to burst?

www.chemistryworld.org



www.chemistryworld.org54 | Chemistry World | January 2011

Endangered elements

causes the structure to swell,’ explainsWilliams. ‘The surface swells but theinside doesn’t, creating stresses thatcause the material to break apart.’

Williams has managed to make newmagnets by pressing the resulting powder together and heating it. Themagnets are not top-spec but canbe used in motors. ‘We can also addextra neodymium and dysprosiumand change it to a different grade of material,’ explains Williams. ‘Wewant to take it to the next step wherewe’re actually collecting scrap andreprocessing it into magnets.’

Meanwhile, researchers at theUniversity of Leeds, UK, have founda way to reclaim rare earth oxidescheaply from the waste streamfrom refining titanium dioxide. Thetitanium dioxide industry ‘hates’ therare earths that contaminate theirfeedstock, explains project leaderAnimesh Jha.

Rare earth chlorides haveextremely high boiling points, thanksto strong nuclear forces. Working with UK company MillenniumChemicals (now Cristal Global),Jha’s team set about trying to purifylower grade titanium tetrachloridefeedstock. The process that they cameup with involves roasting aluminatematerials with alkali. ‘During roasting the dispersed rare earth mineralsflocculate in the highly alkalinemedium,’ explains Jha. The metaloxides – of neodymium, cerium,lanthanum and praseodymium –

form a separate layer that floatsdespite its high density, thanks torepulsion between the OH groupssurrounding the metals. ‘Ourtitanium dioxide process has a verylow carbon footprint compared tothe standard acid leaching process,’says Jha.

Jha is currently seeking funding forthe next project stage – separating outthe component rare earth oxides. Therare earth oxides all have very similarproperties and Jha has a difficult taskin store.

We all have a difficult time ahead

and it is hard to see how short-termshortages of rare earth elementswill be addressed. Let’s hope thatthe wind of change will blow acrossthe West and give scientists theintellectual and financial boostneeded for a recycling revolution.

Emma Davies is a freelance sciencewriter based in Bishop’s Stortford, UK

Additional reporting by Rebecca Renner, a freelance science writerbased in Pennsylvania, US

says. There are projects to reduceand recycle rare earths. Whencomputers are discarded the harddrives are dismantled so as to destroyany data. Andy Williams’s team atthe University of Birmingham, UK,has found a neat way to turn theirneodymium magnets into powder,simply by exposing them to hydrogengas at atmospheric pressure.

‘Hydrogen goes into the spacesbetween the neodymium atoms and

currently only available from Chinaand US industry officials have toldthe GAO that it would take at leasttwo years to develop a pilot plant thatcould refine the oxides to metals.

There is a light

So far, so gloomy. Yet Pitts sees thesituation as a ‘huge opportunity’ forchemists to help recover the elements.

‘We should be scared but equallyexcited about the opportunities,’ he

Modern agriculture depends on phosphorus, whichis mostly obtained from mined phosphate rock.Phosphorus is typically combined with sulfuric acid,nitrogen and potassium in fertilisers. Scientists withthe Global Phosphorus Research Initiative estimatethat within 30 to 40 years there won’t be enoughphosphorus from mining to meet agricultural

demand, and predict a global peak in 30 years.

Yet phosphorus is relatively easy to recoverfrom water systems. Every year the globalpopulation excretes around three milliontonnes of phosphorus in urine and faeces andhighly populated cities have been described asphosphorus hotspots. If urine can be kept separatefrom the rest of the sewage, it can be applied

straight to the fields. In some parts of Sweden, allnew toilets must be able to divert urine for storageand use by local farmers.

UK water company Thames Water is building a‘nutrient recovery facility’ to remove a compoundcalled struvite, which contains phosphorus andammonia, from sewage at its works in Slough. Theplant is scheduled to begin operations in mid-2011.

The phosphorus extracted from Slough’s

wastewater is predicted to form 150 tonnes of

phosphate fertiliser pellets per year which can be

spread directly onto soil.

The struvite blocks pipes and causes water

companies real headaches. ‘This project is

a classic win-win,’ says Piers Clark, Thames

Water’s director of asset management. ‘Wesolve a costly problem and in so doing provide a

renewable form of phosphate.’Phosphorus can be reclaimed from wastewater

Taking the P

Praseodymium, cerium,

lanthanum, neodymium,

samarium and gadolinium

oxides – their similar

properties make themdifficult to separate

P E G G Y G R E B / U S D E P A R T M E N T O F A G R I C U L T U R E / S C I E N C E P H O T O L I B R A R Y

B R Y C

E R I C H T E R , U N I V E R S I T Y O F W I S C O N S I N - M A D I S O N , U S

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Endangered Elements - Critical Thinking_tcm18-196054