Researchers identify supply risk for 62 critical elements
How critical the future supply of all 62 metals and transition metals of the periodic table is, Thomas Graedel from Yale University in New Haven and his colleagues have now comprehensively determined for the first time. Over a period of five years they covered not only the resources and reserves of individual raw materials, but also whether bottlenecks threatened because of extremely unequal distribution of deposits or other socio-political aspects, how great the environmental risk of mining is and whether the element in question is replaced by another can.
The result: At least for iron, zinc, copper, aluminum and some other metals that have been in use for a long time, things are looking relatively good: "They are relatively common and are geographically widely distributed," explains Graedel. However, gold, mercury and some platinum group metals can only be extracted with considerable environmental impact.
Local occurrence, political risks
The situation is different with some metals, which are needed for electronics and thin-film solar cells, among other things: There is a risk of a shortage of supplies especially with indium, arsenic, thallium, antimony, silver and selenium. "These metals only have small, geographically narrow deposits and are usually only extracted as by-products of other metals."
This also looks similarly critical for other rare earth metals. 90 to 95 percent of these rare earths are coming from ChinaTherefore, the researchers here see enormous risks for a shortage. On the other hand, political instability could threaten the supply of tantalum. Because much of this metal is being promoted in the civil war-ridden Democratic Republic of the Congo.
No replacement in sight
According to the researchers, another group of metals could become scarce because demand is high but there are no adequate substitutes. This also applies to some metals that are used before all, as alloys in steel. This group includes indium, chromium, magnesium, manganese, rhodium, yttrium, and some rare earth metals.
"It is undisputed that the modern technology of our world is completely dependent on the constant availability of all these metals - now and in the future," the researchers state. "It would therefore be very short-sighted if we were to exploit one or more metals to such an extent that there would be nothing left for future technologies."
It does not work without recycling
Therefore, according to the scientists, there is no way to improve the recycling of these metals from electronic waste past. However, this is particularly difficult with the rare high-tech raw materials - which is also due to the design of many modern devices. “Some metals, such as lead, are usually found in larger components and are already being recycled to a large extent,” explains Graedel.
But this is not the case with many rare earths that are already in short supply. These are often installed in such a way that they can hardly be separated from the remaining components. “Our results are therefore also a signal to designers to think more about what happens to their products when they are no longer needed,” says Graedel. (Proceedings of the National Journal Academy of Sciences, 2015; doi: 10.1073 / pnas.1500415112)
