Recycling rare earth metals
Amid changing technology trends, more rare earth metals are required to meet our needs – and patent protection may be one solution. Chris Hamer and Laura Clews of Mathys & Squire report
1 minute read
Most people are unaware of rare earth metals, which are responsible for making technology smaller, lighter and more powerful. They are used in everything from optical fibres to mobile phones, catalytic converters to guidance systems, lasers and radar systems. Most electric vehicles and wind turbines use the rare earth elements, neodymium iron boron permanent magnets (NdFeB), for their high-performance electric motors. Rare earth metals are not, in fact, rare and are relatively abundant in nature, but they are found in low concentrations in remote areas and are hazardous and costly to extract. China accounts for 90-95% of global supply and recent economic issues have increased the risks of there being a dominant supplier. Many companies are looking at alternative components or funding research into recycling these precious metals. The market will be worth $14.43 billion by 2025, so companies researching recycling are carefully protecting their innovative methods with robust IP strategies.
Technology is a fundamental part of our everyday life, including how we communicate, travel, entertain ourselves and even how we power our gadgets, but very few of us ever question how sustainable our ever-increasing dependence on technology actually is.
What are rare earth metals?
Until recently, most people were unaware of the central role that rare earth metals play in modern day life. While this little group of metals may not be present in significant volumes within current technology, they are responsible for making technology smaller, lighter and more powerful than before. Rare earth metals are used in everything from optical fibres to mobile phones; catalytic converters to green technology; and are even responsible for providing the sharper and more vivid colours in our flat screen televisions and tablets. These metals have even been identified as essential for modern day defence applications, for example in guidance systems, lasers, and radar and sonar systems.
Given our increasing dependence on technology, our desire to own the latest gadgets and ever-expanding research into green technology, how can we ensure that there is a sufficient supply (both actual and economic) of these rare earth metals to meet our needs?
Fortunately, rare earth metals, such as cerium (Ce), dysprosium (Dy), lanthanum (La), neodymium (Nd), scandium (Sc), terbium (Tb), thulium (Tm), ytterbium (Yb) and yttrium (Y), are not as rare per se as the name suggests; in fact, they are relatively abundant in nature. The main barrier to supplying these metals is that they are only found in low concentrations in remote parts of the world and are hazardous and costly to mine and process.
One important area of developing technology is renewable energy. At the 2015 Paris Climate Conference, it was agreed to increase efforts to limit climate change, including increasing the use of electric vehicles. Several countries have set ambitious sales and/or stock targets regarding vehicle electrification as guidance for creating national roadmaps and for gathering support from policymakers. Among various uptake scenarios, the International Energy Agency and the Electric Vehicles Initiative, a multi-government policy forum, presented an aggregated global deployment target of 7.2 million in annual sales of electric vehicles and 24 million in vehicles stock by 2020.
Most electric vehicles (with the exception of Teslas) use neodymium iron boron permanent magnets (NdFeB), which are essential for the production of high-performance electric motors. Such magnets contain neodymium (Nd), praseodymium (Pr), and dysprosium (Dy) rare earth elements.
Cerium, an example of a rare earth metal
Based on current technology, a permanent magnet synchronous-traction motor for an electric vehicle needs between 1 and 2 kg NdFeB (Neodymium Iron Boron) depending on the motor power, car size, model, etc. Therefore, based on the current technology, to meet the global deployment target of 7.2 million electric vehicle sales in 2020, between 7,200 and 14,400 tonnes of NdFeB magnets would need to be manufactured. This would inevitably require a significant increase in the annual demand for NdFeB magnets in electric vehicles by up to 14 times in just five years.
In addition, many wind turbines also rely on NdFeB magnets to function. In 2015, the global demand in rare earth metals for permanent magnets for use in wind turbines was around 2,500 tonnes. Due to the increasing demand for renewable energy, this value has been predicted to increase to 7,000 tonnes in 2020.
The two examples presented above simply highlight the dramatic increase in demand for rare earth metals in the coming years and does not even take into consideration the reported 1.5 billion smartphones sold in 2017 or the estimated 16 million smartwatches sold by Apple in 2017.
While global resources of rare earth metals have been estimated at around 110 million tonnes, the global supply of these metals is limited due to the cost, complexity and environmentally hazardous process of extracting and separating them, as well as the producers themselves.
At present, China accounts for around 90 to 95% of the global market for rare earth metals. As the environmental regulations in China are not as strict as those in Europe or the US, it has been possible for China to produce these metals at a much lower cost compared to other countries and, therefore, out-compete mines like Mountain Pass in the US. However, recent global economic issues mean there is significant risk in there only being a single large supplier.
Profile 1: Seren Technologies
One UK company tackling this issue head on is Seren Technologies. This business has developed a revolutionary extraction method for recycling rare earth methods using ionic liquids. An ionic liquid is a salt in which the ions are poorly coordinated, resulting in these solvents being liquid below 100°C, or even at room temperature. One benefit of using ionic liquids in recycling methods is that they have lower levels of volatility and flammability compared to the organic solvents (such as those used in previously-known recycling methods), providing a safer and more environmentally-friendly method. In fact, this new recycling process has been reported to have an environmental footprint that is one hundred times smaller than other known recycling methods.
Seren Technologies’ research is based on the use of hydrophobic ionic liquids comprising a nitrogen donor and additional electron donating groups which act as a molecular recognition ligand to improve the selectivity and levels of recovery of rare earth metals. It has been reported that this new patented process (WO 2018/109483) can separate mixtures of dysprosium and neodymium with a selectivity of over 1000:1 in a single processing step, meaning that this research can not only lead to increased levels of recycled rare earth metals but that this can be achieved in a less time-consuming, more cost-efficient and a more environmentally-friendly way.
Seren Technologies opened its pre-commercial permanent magnet recycling plant at the Wilton Centre in the north of England on December 3 2018, illustrating 98% selectivity of rare earth metals in a single separation step, taking only two hours, marking a significant reduction in the time required to select these rare earth metals.
With the aim to bring this technology to market on an industrial scale, it could represent a significant leap forward in the viability of recycling rare earth metals in a safer and more economically-viable way.
Extraction and purification
The process of extracting and purifying rare earth metals typically requires the following steps:
1) extraction of a rare earth metal-containing material – for example mining an ore containing rare earth metals;
2) increasing the concentration of the rare earth material;
3) purifying the rare earth metal containing material – this is most commonly achieved through solvent extraction (the process of partially removing a substance from one solution by dissolving it in another, immiscible solvent in which it is more soluble), wherein the separated metals are in the form of carbonates, oxalates or hydroxides. However, due to the similar physical and chemical properties of rare earth metals, it can be difficult to separate these mixtures into individual components, so producing a full separation of rare earth metal may require hundreds of process steps; and
4) refining the extracted rare earth metals – using complex processing including converting separated rare earth compounds to metals using molten salt electrolysis and metallothermic reduction methods; such methods require large electrical inputs.
Previously, recycling methods for rare earth materials have often been based on a multiple-stage solvent extraction, such as the one discussed above, requiring large amounts of chemicals and energy input. While several alternative methods have been proposed over the years, very few have been scaled up and tested at the required production volumes.
Profile 2: Worcester Polytechnic Institute
Across the pond, the US government has been funding research into methods of effectively recycling rare earth metals. One project, by the Worcester Polytechnic Institute, has focussed on extracting rare earth metals from machinery without the requirement of first dismantling the machine to be recycled. Typically, rare earth materials are contained within the inner most parts of the machine and are, therefore, not readily accessible. Accordingly, previously known methods have required substantial time and cost in order to access the relevant machinery part for recycling.
In response to these issues, Worcester Polytechnic Institute has produced a low-temperature method of extracting rare earth metals from fragmented end-of-life machinery. The patented method (US 2016/208364) requires the steps of first demagnetisation of the metal through heating, for example the end-of-life machinery can be heated in a furnace at a temperature of at least 400°C for 60 minutes in order to demagnetise metals contained therein. The material is then shredded to break the present magnets. Finally, the rare earth metals are extracted through the use of a leaching solution via hydrochloric acid to produce a solution of the dissolved magnet material, followed by precipitating the rare earth metals using oxalic acid.
It has been reported that the method provides recovery efficiencies of up to 82% with rare earth metals having a purity of over 99%.
Rare earth metals and politics
The vast majority of the global market for rare earth metals is dependent on the production in China. However, does this considerable reliance on one source of rare earth metals make technology, renewable energy and defence markets vulnerable?
In 2010, China announced that the amount of rare earth metals to be exported would be reduced due to domestic requirements and concerns over the environmental effects of mining. The amount of rare earth metals exported from China was dramatically reduced from 50,145 tonnes in 2009 to 31,130 tonnes in 2012, causing a sharp increase in the cost of exported rare earth metals. In 2012, Japan, the US and the EU complained to the World Trade Organization (WTO) about these restrictions. Although China cited environmental reasons for the reduction of export quotas, the WTO ruled on March 26 2014 that China's export limits violated the WTO rules. However, the amount of rare earth metal ores mined in China in 2016-2017 only amounted to around 105,000 tonnes.
Therefore, the current supply of rare earth metals is failing to meet the ever-increasing demand in the modern world.
To add further concerns, it would seem that politics can also play a significant role in the supply of rare earth metals from China and, therefore, the possibility of manufacturing technology and defence applications.
While recycling rare earth metals would be a fitting solution to the current crisis, previously used methods of recycling rare earth metals still require the use of toxic/hazardous chemicals
In 2010, China reportedly blocked exports of rare earth metals to Japan for a period of time following a dispute regarding the detention of a Chinese fishing trawler captain, however the dispute between these two countries was ultimately resolved and exportation of the metals resumed.
Worryingly, it seems that history may be repeating itself following a statement made in May by US Trade Representative Robert Lighthizer regarding a proposition to increase tariffs on imports from China:
"Earlier today, at the direction of the president, the United States increased the level of tariffs from 10% to 25% on approximately $200 billion worth of Chinese imports. The president also ordered us to begin the process of raising tariffs on essentially all remaining imports from China, which are valued at approximately $300 billion."
Clearly, China does not consider the enforcement of these new US tariffs to be reasonable and there is concern that China may use its considerable dominance in the supply of rare earth metals as leverage in this trade dispute. Reporting comments by Wang Shouwen, a vice commerce minister for China, the newspaper News of the Communist Party of China said that:
"Even after China overcame difficulties to find pragmatic solutions to many issues raised by the US, it still wanted a yard after China offered an inch," said Wang, who is part of the Chinese negotiating team, noting that the US insisted on 'unreasonable' demands, including terms that violate China's sovereignty."
In view of this ongoing dispute, there is growing concern that China will consider restricting the export of rare earth metals to the US in retaliation if the tariff increase on the importation of Chinese goods is not lifted (not surprisingly, rare earth metals were excluded from US tariff increases.).
Profile 3: Iowa State University Research Foundation
Further research funded by the US government includes the work by the Iowa State University Research Foundation (US 2018/312941). The disclosed method recycles rare earth metal-containing materials from end-of-life products such as permanent magnets from computer hard disk drives, electric motors and batteries. The patented process comprises the steps of contacting the rare earth metal-containing material with an aqueous solution of a copper (II) salt to dissolve the material in the solution. The dissolved rare earth metal is then precipitated from the aqueous solution as rare earth metal oxalate, sulphate or phosphate. The precipitate is then calcined to produce a rare earth metal oxide.
It has been reported that the above method can provide over 99% purity of the rare earth metals in the form of oxides, sulphates or phosphates.
Recycling rare earth metals
As fears grow that the availability of rare earth metals may soon be restricted, many companies outside of China are looking at ways to limit their dependency on China for the supply of rare earth metals, and are now turning to possible alternative components or funding research into methods of recycling these precious metals. The ability to provide an environmentally-friendly, cost-effective method of recycling rare earth metals providing higher levels of purity and selectivity could meet a significant percentage of the demand in, for example, EU countries, the US and Japan, but does such a process exist?
While recycling rare earth metals (often referred to as 'urban mining') would be a fitting solution to the current crisis, previously used methods of recycling rare earth metals still require the use of toxic/hazardous chemicals; a large number of processing steps (therefore requiring high process times, which increase the costs of the recovered metals); and have poor selectivity, meaning that lower amounts of rare earth metals are actually recovered from the recycling process. All of these issues are leaving many countries wondering how they can possibly keep up with the growing demand for these versatile metals.
Fortunately, many companies have undertaken significant research to resolve these problems. Given that the global rare earth metal market was reported to be worth $8.10 billion in 2018 and has been estimated to be worth $14.43 billion by 2025, the companies researching cost-effective and highly selective recycling methods are, of course, carefully protecting these innovative methods from third party use. For example, obtaining patent protection, with particular emphasis on protecting these methods in many of the countries in which such a recycling process may be performed, plays a significant role in the essential IP protection (see profiles 1, 2 and 3).
As some companies, such as Seren Technologies (see profile 1), seem to be close to making their recycling methods available to the public, it would seem a real possibility that the amount of rare earth metal that can be efficiently recycled can be significantly increased in the near future, thereby reducing our dependence on external providers. However, whether this can be achieved before the cost of these metals increases as an effect of ever growing demand or further political turmoil remains to be seen.
Chris Hamer is a partner and Laura Clews a managing associate at Mathys & Squire in London.