Rare earth elements – how to handle future challenges
Rare earth elements (REE) are common in the earth’s crust, but in low concentrations. Their extraction is labor intensive and comes with a considerable environmental impact. Mostly used as chemical catalysts, rare earth elements are also indispensable for the energy transition and global electrification. The US Defense Advanced Research Projects Agency (DARPA) looks at microbes to process rare earth elements. What could be the implications for Switzerland?
What are rare earth elements (REE)? Rare earths aren’t really rare. However, these elements are dispersed and mixed with large amounts of other elements. Their average concentration in rocks is very low. They must be extracted from the surrounding rocks with labor intensive and environmentally burdening processes. Rare earth elements are a group of seventeen chemical elements (Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). They are also called the “vitamins” of the industry because they are fundamental ingredients across much of the high-tech manufacturing industry. Like vitamins they are used in small quantities only and they are indispensable. An electric car contains several kilograms of neodymium or lanthanum. A wind turbine generator contains hundreds of kilograms of dysprosium. Each computer, cell phone or other electronic device depends on rare earth elements. The rare earth element gadolinium (Gd) is used as contrast agent in magnetic resonance imaging (MRI).
China dominates the market Rare earth elements can be found in different parts of the world. However, as of today there are only three mines in China and one in the Western US, in Mountain Pass Mine, California, in operation. The US mine was actually closed in the 1980s only to be reopened in 2017. The extraction from the ore is only done in China. The consequences are that China not only dominates the REE market with a share of 90 percent, but it is also the only country that operates the full production chain from ores to REE metals at industrial scale. As higher environmental standards will most probably lead to a production decline in China, there is need for action to find alternative REE sources to secure the supply of these industrially important raw materials.
Existing conflicts of interest Classic open mining and longwall mining are energy intensive and environmentally burdening large-scale processes: conflicts are inevitable. A large deposit of lithium was discovered in Barroso, northern Portugal in an area which was recently declared a world heritage site. The British mining company Savannah Resources plans to extract rare earth elements in opencast mining (quarrying). Significant deposits of rare elements were recently discovered in arctic Sweden, 600 kilometres north of Stockholm. It seems to be Europe’s largest known rare earth deposit. The government-owned company LKAB plans to start extraction within the next 10 to 15 years using longwall mining. It is key that the mining of these critical metals is carried efficiently, also considering new innovative approaches to reduce the environmental impact to the maximum.
The importance of recycling In the frame of the annual topic “security of supply”, SATW explores and discusses several shortage problems and solutions with an actual focus on energy, drug shortages and phosphorus. There are differences between shortages of drugs or plastic as well as between rare earth elements and phosphorus. The only Swiss source of the latter are waste materials. Sewage sludge is the only domestic source for phosphorus [https://www.satw.ch/de/blog/die-klaeranlage-als-goldgrube] and for rare earth elements it is end of life waste materials such as batteries, discarded phones, computers, and the like. According to UN estimations less than 20 percents of the roughly 54 million tons of waste globally produced every year are recycled. This represents tens of billions of Swiss Francs lost every year. In 2030, over 1.5 million tons of car batteries will need to be recycled. In Switzerland, over 26 kilograms of electronic waste are produced per capita and year.
Metal recycling works well for gold, iron, or copper. But we do not have good methods to recycle rare earth elements. One important reason is the lack of a highly specific separation method for these metals. So far the recycling is done using the following methods:
1. The waste is shredded to powder and REEs are extracted2.
Pyrometallurgical methods separating REEs at very high temperature
3. Liquid-liquid extraction of dissolved REEs
Biomining and its impact Lanmodulins are highly selective protein chelators for lantinides, which open new possibilities for the liquid-liquid extraction for rare earth element recycling and rare earth mining. Some plants and microbes have long been known to accumulate metals. There exist bacteria which are capable to bind specifically rare earth elements. For example, the methylotrophic bacterium Methylobacterium extorquens needs rare earth elements such as Lanthanides as enzyme cofactors. Lanmodulins, these highly selective lanthanide-binding proteins, are essential for the capture of these essential rare earth element and survival of these microorganism. Experts at the Pennsylvania State University have shown that these rare earth elements binding proteins can be used industrially for land mining, battery and electronic waste recycling. One conceivable way to use them industrially is to produce the protein in a recombinant host, isolate and immobilize the protein on a solid support or a carrier. The Swiss investor and entrepreneur Oliver Siegel is in the process establishing a rare earth recycling start-up using immobilized lanmodulin for value creation. The selectivity of the recombinant protein can also be adapted to actinides (radioactive metals) for example. The original plan was to incorporate the start-up in Switzerland. Due to high costs the start-up will finally be located in Vienna, Austria.
Joining forces The topic is of high importance and has an even broader scope. The American Chemical Society (ACS) published 44 chemical elements which will face supply limitations in the coming years. Whether the novel biotechnological approach and methodology described above could be applied to other recycling systems, metal and non-metal, remains to be seen.
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Contact: Hans‐Peter Meyer, Expertinova AG, SATW Member, Head of Scientific Advisory Board SATW