[tt] Fwd: New Scientist, depletion of platinum, iridium, other elements

[Jef]

Recycling is probably cheaper than mining the moon or asteroid belt.

>http://tinyurl.com/2b8jhc (subscription)
>
>Earth's natural wealth: an audit
>
>23 May 2007
>NewScientist.com news service
>David Cohen
>
>"I GET excited every time I see a street cleaner," says Hazel Prichard.
>It's what they collect in their sacks that gets her juices flowing,
>because the grime and litter they sweep up off the streets is laced with
>traces of platinum, one of the world's rarest and most expensive metals.
>The catalytic converters that keep exhaust pollutants from cars, trucks
>and buses down to an acceptable level all use platinum, and over the
>years it is slowly but steadily lost through these vehicles' exhaust
>pipes. Prichard, a geologist at the University of Cardiff in the UK,
>reckons that tonnes of the stuff is being sprayed out onto the world's
>streets and highways every year, and she is hunting for places where it
>is concentrated enough to be worth recovering. One of her prime targets
>is the waste containers in road-sweeping machines.
>
>This could prove lucrative, but Prichard is motivated by something far
>more significant than the chance of a quick buck. Platinum is a vital
>component not only of catalytic converters but also of fuel cells - and
>supplies are running out. It has been estimated that if all the 500
>million vehicles in use today were re-equipped with fuel cells,
>operating losses would mean that all the world's sources of platinum
>would be exhausted within 15 years. Unlike with oil or diamonds, there
>is no synthetic alternative: platinum is a chemical element, and once we
>have used it all there is no way on earth of getting any more. What
>price then pollution-free cities?
>
>It's not just the world's platinum that is being used up at an alarming
>rate. The same goes for many other rare metals such as indium, which is
>being consumed in unprecedented quantities for making LCDs for
>flat-screen TVs, and the tantalum needed to make compact electronic
>devices like cellphones. How long will global reserves of uranium last
>in a new nuclear age? Even reserves of such commonplace elements as
>zinc, copper, nickel and the phosphorus used in fertiliser will run out
>in the not-too-distant future. So just what proportion of these
>materials have we used up so far, and how much is there left to go round?
>
>Perhaps surprisingly, given how much we rely on these elements, we can't
>be sure. For a start, the annual global consumption of most precious
>metals is not known with any certainty. Estimating the extractable
>reserves of many metals is also difficult. For rare metals such as
>indium and gallium, these figures are kept a closely guarded secret by
>mining companies. Governments and academics are only just starting to
>realise that there could be a problem looming, so studies of the issue
>are few and far between.
>
>Armin Reller, a materials chemist at the University of Augsburg in
>Germany, and his colleagues are among the few groups who have been
>investigating the problem. He estimates that we have, at best, 10 years
>before we run out of indium. Its impending scarcity could already be
>reflected in its price: in January 2003 the metal sold for around $60
>per kilogram; by August 2006 the price had shot up to over $1000 per
>kilogram.
>
>Uncertainties like this pose far-reaching questions. In particular, they
>call into doubt dreams that the planet might one day provide all its
>citizens with the sort of lifestyle now enjoyed in the west. A handful
>of geologists around the world have calculated the costs of new
>technologies in terms of the materials they use and the implications of
>their spreading to the developing world. All agree that the planet's
>booming population and rising standards of living are set to put
>unprecedented demands on the materials that only Earth itself can
>provide. Limitations on how much of these materials is available could
>even mean that some technologies are not worth pursuing long term.
>
>Take the metal gallium, which along with indium is used to make indium
>gallium arsenide. This is the semiconducting material at the heart of a
>new generation of solar cells that promise to be up to twice as
>efficient as conventional designs. Reserves of both metals are disputed,
>but in a recent report René Kleijn, a chemist at Leiden University in
>the Netherlands, concludes that current reserves "would not allow a
>substantial contribution of these cells" to the future supply of solar
>electricity. He estimates gallium and indium will probably contribute to
>less than 1 per cent of all future solar cells - a limitation imposed
>purely by a lack of raw material.
>
>To get a feel for the scale of the problem, we have turned to data from
>the US Geological Survey's annual reports and UN statistics on global
>population. This has allowed us to estimate the effect that increases in
>living standards will have on the time it will take for key minerals to
>run out (see Graphs). How many years, for instance, would these minerals
>last if every human on the planet were to consume them at just half the
>rate of an average US resident today?
>
>The calculations are crude - they don't take into account any increase
>in demand due to new technologies, and also assume that current
>production equals consumption. Yet even based on these assumptions, they
>point to some alarming conclusions. Without more recycling, antimony,
>which is used to make flame retardant materials, will run out in 15
>years, silver in 10 and indium in under five. In a more sophisticated
>analysis, Reller has included the effects of new technologies, and
>projects how many years we have left for some key metals. He estimates
>that zinc could be used up by 2037, both indium and hafnium - which is
>increasingly important in computer chips - could be gone by 2017, and
>terbium - used to make the green phosphors in fluorescent light bulbs -
>could run out before 2012. It all puts our present rate of consumption
>into frightening perspective (see Diagram).
>
>Our hunger for metals and minerals may not grow indefinitely, however.
>When Tom Graedel and colleagues at Yale University looked at figures for
>the consumption of iron - one of our planet's most plentiful metals -
>they found that per capita consumption in the US levelled off around
>1980. "This suggests there might be only so many iron bridges, buildings
>and cars a member of a technologically advanced society needs," Graedel
>says. He is now studying whether this plateau is a universal phenomenon,
>in which case it might be possible to predict the future iron
>requirements of developing nations. Whether consumption of other metals
>is also set to plateau seems more questionable. Demand for copper, the
>only other metal Graedel has studied, shows no sign of levelling off,
>and based on 2006 figures for per capita consumption he calculates that
>by 2100 global demand for copper will outstrip the amount extractable
>from the ground.
>
>So what can be done? Reller is unequivocal: "We need to minimise waste,
>find substitutes where possible, and recycle the rest." Prichard,
>working with Lynne Macaskie at the University of Birmingham in the UK,
>has found that platinum makes up as much as 1.5 parts per million of
>roadside dust. They are now seeking out the largest of these urban
>platinum deposits, and Macaskie is developing a bacterial process that
>will efficiently extract the platinum from the dust.
>
>Other metals could be obtained in equally unorthodox places. Cities are
>huge stores of metals that could be repurposed, Kleijn points out.
>Replacing copper water pipes with plastic, say, would free up large
>quantities of copper for other uses. Tailings from worked-out mines
>contain small amounts of minerals that may become economic to extract.
>Some metals could be taken from seawater. "It's all a matter of energy
>cost," he says. "You could go to the moon to mine precious materials.
>The question is: could you afford it?"
>
>These may sound like drastic solutions, but as Graedel points out in a
>paper published last year (Proceedings of the National Academy of
>Sciences, vol 103, p 1209), "Virgin stocks of several metals appear
>inadequate to sustain the modern 'developed world' quality of life for
>all of Earth's people under contemporary technology." And when resources
>run short, conflict is often not far behind. It is widely acknowledged
>that one of the key motives for civil war in the Democratic Republic of
>the Congo between 1998 and 2002 was the riches to be had from the
>country's mineral resources, including tantalum mines - the biggest in
>Africa. The war coincided with a surge in the price of the metal caused
>by the increasing popularity of mobile phones (New Scientist, 7 April
>2001, p 46).
>
>Similar tensions over supplies of other rare metals are not hard to
>imagine. The Chinese government is supplementing its natural deposits of
>rare metals by investing in mineral mines in Africa and buying up
>high-tech scrap to extract metals that are key to its developing
>industries. The US now imports over 90 per cent of its so-called "rare
>earth" metals from China, according to the US Geological Survey. If
>China decided to cut off the supply, that would create a big risk of
>conflict, says Reller.
>
>Reller and Graedel say urgent action is required. Firstly, we need
>accurate estimates of global reserves and precise figures for
>consumption. Then we need to set up an accelerated programme to recycle,
>reuse and, where possible, replace rare elements with more abundant
>ones. Without all this, any dream of a more equitable future for
>humanity will come to nothing.
>
>Governments seem, at last, to be taking the issue seriously, and next
>month an OECD working group will be convened to come up with some of the
>answers. If that goes to plan, we will soon at least have a clearer idea
>of the problem. Whether any solution to looming global shortages can
>then be found remains to be seen.
>
> From issue 2605 of New Scientist magazine, 23 May 2007, page 34-41