MY LAST POST on the relationship between metals and militias in Eastern DRC included references to coltan, used in producing small-volume tantalum capacitors for mobile devices, and cassiterite, an ore of tin, which the electronics industry is using more and more of in lead-free solders. This prompted a senior colleague in the British Computer Society to ask what other ‘troublesome’ elements might cause problems further down the line.

Indium

ONE CANDIDATE IS INDIUM, the current principal use of which (70%) is to make the transparent indium tin oxide electrodes used in liquid crystal displays. Indium is found in nature only as a tiny proportion of other metal ores, and is extracted from tailings, usually from zinc mining operations. About 470 tonnes of indium are extracted this way each year, worldwide.

Canada is a leading producer, and the largest single source is the Teck Cominco refinery in British Columbia. Some other sources are in Portugal, Peru, southern China and Khazakhstan — a diverse and widespread range. The main worry with indium is nothing to do with dodgy politics, but simply whether there will be enough to meet demand in the future.

LCD technology is not only pervasive on laptops, desktops and just about every mobile technology you can imagine, but also now for televisions. But there is another growing source of demand for indium in the form of a promising thin-film solar cell technology called ‘CIGS’ (copper indium gallium selenide).

There are two ways in which an indium supply crisis may be averted, however. One is through developing extraction processes that improve on the current 20% yield, and extend the process to other metal ores such as copper — increased prices for indium would make that a viable proposition. The other is through recycling, which in fact accounts for 650 tonnes of indium per year, more than from mining, according to a report from the Indium Corporation to a photovoltaics conference in Milan in late 2007.

However, it seems likely that this ‘recycling’ term principally means the in-factory recovery of the 70% of indium tin oxide (ITO) which ‘misses the target’ when LCD transistor arrays are being deposited. I would feel rather happier if I knew that LCD displays at the end of their lives were being scavenged for their rare elements rather than ending up in landfill — true ‘post-consumer’ indium recycling.

And maybe, in any case, we will see ITO replaced entirely in LCD production before long. An exciting alternative way of making transparent electrodes would be to use graphene — engineered one-atom-thick sheets of linked carbon atons which a Wikipedia article charmingly describes as ‘atomic-scale chicken wire’! And a scarcity of carbon is simply unthinkable.

Lithium: the Li-ion roars but for how long?

A SHORTAGE OF LITHIUM, on the other hand, could be a real bugbear. It is scarcely 17 years since Sony produced the first commercially available lithium-ion (Li-ion) rechargeable batteries, and they have become the battery of choice for portable devices such as laptops, camcorders, digital cameras and mobile phones. They have an excellent energy-to-weight ratio, they lose their charge very slowly when not in use, and they do not have that hated ‘memory effect’ which nickel-cadmium cells suffer from.

Lithium-ion technology has had its problems. While in use, the anode generates heat, and the cathode is a potential source of oxygen; and given the reactivity of lithium, batteries have been known to explode. Apple Computer is just one of several computer companies that had to embark on expensive battery recall and replacement programmes due to exploding Li-ion batteries. The problem is solved by building monitoring and control circuitry into the batteries, and there are ongoing programmes of research to improve reliability, overcome the ‘aging’ problem (Li-ion batteries slowly deteriorate in capacity from the day they are born, and faster if they become hot), and still further improve their energy density.

The problem with lithium is, although it is relatively common, it is dispersed at low levels of concentration throughout the earth’s rocks and oceans, making it uneconomic to retrieve except for a few locations where is is concentrated, such as in the granitic rock spodumene. Some 80,000 tons of lithium is extracted from such rocks in Western Australia, China and Chile. Another source is from ancient alkaline brine lakes in China and Argentina.

Is this enough? It depends of the world’s appetite for lithium, and that may be set to increase enormously due to the suitability of Li-ion batteries for automotive applications: either fully electric vehicles, or petrol-electric hybrids such as the Toyota Prius. These vehicles use serious amounts of lithium in their batteries. Mitsubishi, which plans to introduce its own electric car soon, estimates that unless new sources of lithium are found, demand will outstrip supply in ten years, and prices will soar.

There is one truly enormous reserve of lithium in the world. More than half of the world’s reserves of lithium are in one place: the Salar de Uyuni, the world’s largest (10,582 km2) and highest (3,650 m) salt flat, in the south eastern corner of Bolivia. The Salar de Uyuni contains an estimated 10 billion tons of salt, but less than 25,000 tons is extracted each year, and by miners belonging to a co-operative. And as for lithium extraction, there is none.

BBC news on 9 November published an article by Damian Kahya — ‘Bolivia holds key to electric car future’ — about how industry regards the Salar as the answer to lithium shortages in the future. But Bolivia’s socialist president, Evo Morales, is not about to let any foreign company in to loot the lithium. After centuries in which foreigners extracted Bolivia’s gold, silver, tin, oil and gas and yet left it one of the poorest countries in Latin America, Morales is determined that in the case of lithium the benefit will accrue to Bolivia.

The Bolivian government has plans to set up a pilot plant, initially producing 1,200 tons a year, in the Salar. Without foreign involvement, the project may take time to scale up to meet the predicted demands of the market for lithium. All of which makes the politics of lithium very interesting indeed.