Rare-earth element

1787: Discovery Rare earths were mainly discovered as components of minerals. The term "rare" refers to these rarely found minerals and "earth" comes from an old name for oxides, the chemical form for these elements in the mineral. The adjective "rare" may also mean strange or extraordinary. 1794–1878: Chemical isolation Anders Gustav Ekeberg, Swedish analytical chemist, chemically isolated the beryllium from the gadolinite but failed to recognize other elements in the ore. After this discovery in 1794, a mineral from Bastnäs near Riddarhyttan, Sweden, which was believed to be an iron–tungsten mineral, was re-examined by Jöns Jacob Berzelius and Wilhelm Hisinger. In 1803, they obtained a white oxide and called it ceria. Martin Heinrich Klaproth independently discovered the same oxide and called it ochroia. It took another 30 years for researchers to determine that other elements were contained in the two ores ceria and yttria. The similarity of the rare-earth metals' chemical properties made their separation difficult. In 1839, Carl Gustav Mosander, an assistant of Berzelius, separated ceria by heating the nitrate and dissolving the product in nitric acid. He called the oxide of the soluble salt lanthana. It took him three more years to separate the lanthana further into didymia and pure lanthana. Didymia, although not further separable by Mosander's techniques, was in fact still a mixture of oxides. In 1842, Mosander separated the yttria into three oxides: pure yttria, terbia, and erbia. All the names are derived from the town name "Ytterby". The earth giving pink salts he called terbium. The one that yielded yellow peroxide he called erbium. By then the number of known rare-earth elements had reached six: yttrium, cerium, lanthanum, didymium, erbium, and terbium. Nils Johan Berlin and Marc Delafontaine tried also to separate the crude yttria and found the same substances that Mosander obtained. In 1860, Berlin named the substance giving pink salts erbium. Delafontaine named the substance with the yellow peroxide, terbium. This confusion led to several false claims of new elements, such as the mosandrium of J. Lawrence Smith, or the philippium and decipium of Delafontaine. Due to the difficulty in separating the metals, and determining the separation is complete, the total number of false discoveries was dozens, with some putting the total number of discoveries at over a hundred. 1879–1930s: Spectroscopic identification There were no further discoveries for 30 years, and the element didymium was listed in the periodic table of elements with a molecular mass of 138. In 1879, Delafontaine used the new physical process of optical flame spectroscopy and found several new spectral lines in didymia. Also in 1879, Paul Émile Lecoq de Boisbaudran isolated the new element samarium from the mineral samarskite. In 1886, the samaria earth was further separated by Lecoq de Boisbaudran. A similar result was obtained by Jean Charles Galissard de Marignac by direct isolation from samarskite. They named the element gadolinium after Johan Gadolin, and its oxide was named "gadolinia". Further spectroscopic analysis between 1886 and 1901 of samaria, yttria, and samarskite by William Crookes, Lecoq de Boisbaudran and Eugène-Anatole Demarçay yielded several new spectral lines that indicated the existence of an unknown element. In 1901, the fractional crystallization of the oxides yielded europium. In 1839, the third source for rare earths became available. This is a mineral similar to gadolinite called uranotantalum, now called "samarskite", an oxide of a mixture of elements such as yttrium, ytterbium, iron, uranium, thorium, calcium, niobium, and tantalum. This mineral from Miass in the southern Ural Mountains was documented by Gustav Rose. The Russian chemist R. Harmann proposed that a new element he called "ilmenium" should be present in this mineral, but later, Christian Wilhelm Blomstrand, Galissard de Marignac, and Heinrich Rose found only tantalum and niobium (columbium) in it. The exact number of rare-earth elements that existed was highly unclear, and a maximum number of 25 was estimated. Using X-ray spectra Henry Gwyn Jeffreys Moseley confirmed the atomic theory of Niels Bohr and simultaneously developed the theory of atomic numbers for the elements. Moseley found that the exact number of lanthanides had to be 15, revealing a missing element, element 61, a radioactive element with a half-life of 18 years which would be first produced and characterized in 1945. Using these facts about atomic numbers from X-ray crystallography, Moseley also showed that hafnium (element 72) would not be a rare-earth element. Moseley was killed in World War I in 1915, years before hafnium was discovered. Hence, the claim of Georges Urbain that he had discovered element 72 was untrue. Hafnium is an element that lies in the periodic table immediately below zirconium, and hafnium and zirconium have very similar chemical and physical properties. 1940s onwards: Purification In the 1940s, Frank Spedding and others in the United States, during the Manhattan Project, developed chemical ion-exchange procedures for separating and purifying rare-earth elements. This method was first applied to the actinides for separating plutonium-239 and neptunium from uranium, thorium, actinium, and the other actinides in the materials produced in nuclear reactors. Plutonium-239 was very desirable because it is a fissile material. The missing element 61, Promethium, was produced synthetically in 1945, becoming the last rare earth element to be discovered. It does not occur in significant quantities in nature. Between 1985 and 1995 China increased its share in the production of REE from 21% to 60%. The causes of this rise are attributed to tax reduction, favourable credits with were further aided by low labour costs and a lack of environmental regulation. ==Etymology==

The term "rare" in "rare-earth" is a misnomer because they are not actually scarce, but rather because they are only found in compounds, not as pure metals, or perhaps because they were considered exotic at the time of their discovery. The "earth" part refers to an old term for minerals that dissolve in acids and thus are stable to oxidation. They are never found in highly concentrated form, usually being mixed together with one another, or with radioactive elements such as uranium and thorium, and can only be separated from other materials or one another with difficulty. This makes them difficult to purify. ==List of rare-earth elements==

Rare-earth elements or minerals are distinct from minerals or materials described as critical minerals or raw materials, which refers to materials that are considered to be of strategic or economic importance to a country. There is no single list, but individual governments compile lists of materials that are critical for their own economies. A table listing the 17 rare-earth elements, their atomic number and symbol, the etymology of their names, and their main uses (see also Applications of lanthanides) is provided here. Some of the rare-earth elements are named after the scientists who discovered them, or elucidated their elemental properties, and some after the geographical locations where discovered. Classification Before the time that ion exchange methods and elution were available, the separation of the rare earths was primarily achieved by repeated precipitation or crystallization. In those days, the first separation was into two main groups, the cerium earths (lanthanum, cerium, praseodymium, neodymium, and samarium) and the yttrium earths (scandium, yttrium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium). Europium, gadolinium, and terbium were either considered as a separate group of rare-earth elements (the terbium group), or europium was included in the cerium group, and gadolinium and terbium were included in the yttrium group. In the latter case, the f-block elements are split into half: the first half (La–Eu) form the cerium group, and the second half (Gd–Yb) together with group 3 (Sc, Y, Lu) form the yttrium group. The reason for this division arose from the difference in solubility of rare-earth double sulfates with sodium and potassium. The sodium double sulfates of the cerium group are poorly soluble, those of the terbium group slightly, and those of the yttrium group are very soluble. Sometimes, the yttrium group was further split into the erbium group (dysprosium, holmium, erbium, and thulium) and the ytterbium group (ytterbium and lutetium), but today the main grouping is between the cerium and the yttrium groups. Today, the rare-earth elements are classified as light or heavy rare-earth elements, rather than in cerium and yttrium groups. Light versus heavy classification The classification of rare-earth elements is inconsistent between authors. The most common distinction between rare-earth elements is made by atomic numbers. Those with low atomic numbers are referred to as light rare-earth elements (LREE), those with high atomic numbers are the heavy rare-earth elements (HREE), and those that fall in between are typically referred to as the middle rare-earth elements (MREE). Commonly, rare-earth elements with atomic numbers 57 to 61 (lanthanum to promethium) are classified as light and those with atomic numbers 62 and greater are classified as heavy rare-earth elements. Increasing atomic numbers between light and heavy rare-earth elements and decreasing atomic radii throughout the series causes chemical variations. The actual metallic densities of these two groups overlap, with the "light" group having densities from 6.145 (lanthanum) to 7.26 (promethium) or 7.52 (samarium) g/cc, and the "heavy" group from 6.965 (ytterbium) to 9.32 (thulium), as well as including yttrium at 4.47. Europium has a density of 5.24. Geochemical classification The REE geochemical classification is usually done on the basis of their atomic weight. One of the most common classifications divides REE into 3 groups: light rare earths (LREE - from 57La to 60Nd), intermediate (MREE - from 62Sm to 67Ho) and heavy (HREE - from 68Er to 71Lu). REE usually appear as trivalent ions, except for Ce and Eu which can take the form of Ce4+ and Eu2+ depending on the redox conditions of the system. Consequentially, REE are characterized by a substantial identity in their chemical reactivity, which results in a serial behaviour during geochemical processes rather than being characteristic of a single element of the series. Sc, Y, and Lu can be electronically distinguished from the other rare earths because they do not have f valence electrons, whereas the others do, but the chemical behaviour is almost the same. A distinguishing factor in the geochemical behaviour of the REE is linked to the so-called "lanthanide contraction" which represents a higher-than-expected decrease in the atomic/ionic radius of the elements along the series. This is determined by the variation of the shielding effect towards the nuclear charge due to the progressive filling of the 4f orbital which acts against the electrons of the 6s and 5d orbitals. The lanthanide contraction has a direct effect on the geochemistry of the lanthanides, which show a different behaviour depending on the systems and processes in which they are involved. The effect of the lanthanide contraction can be observed in the REE behaviour both in a CHARAC-type geochemical system (CHArge-and-RAdius-Controlled Some ilmenite concentrates contain small amounts of scandium and other rare-earth elements, which could be analysed by X-ray fluorescence (XRF). Properties According to chemist Andrea Sella in 2016, rare-earth elements differ from other elements, in that when looked at analytically, they are virtually inseparable, having almost the same chemical properties. However, in terms of their electronic and magnetic properties, each one occupies a unique technological niche that nothing else can. For example, "the rare-earth elements praseodymium (Pr) and neodymium (Nd) can both be embedded inside glass and they completely cut out the glare from the flame when one is doing glass-blowing." Rare-earth metals tarnish slowly in air at room temperature and react slowly with cold water to form hydroxides, liberating hydrogen. They react with steam to form oxides and ignite spontaneously at a temperature of . These elements and their compounds have no biological function other than in several specialized enzymes, such as in lanthanide-dependent methanol dehydrogenases in bacteria. The water-soluble compounds are mildly to moderately toxic, but the insoluble ones are not. All isotopes of promethium are radioactive, and it does not occur naturally in the earth's crust, except for a trace amount generated by spontaneous fission of uranium-238. They are often found in minerals with thorium, and less commonly uranium. Rare-earth compounds Rare-earth elements occur in nature in combination with phosphate (monazite), carbonate-fluoride (bastnäsite), and oxygen anions. In their oxides, most rare-earth elements only have a valence of 3 and form sesquioxides (cerium forms ). Five different crystal structures are known, depending on the element and the temperature. The X-phase and the H-phase are only stable above 2000 K. At lower temperatures, there are the hexagonal A-phase, the monoclinic B-phase, and the cubic C-phase, which is the stable form at room temperature for most of the elements. The C-phase was once thought to be in space group I23 (no. 199), but is now known to be in space group Ia (no. 206). The structure is similar to that of fluorite or cerium dioxide (in which the cations form a face-centred cubic lattice and the anions sit inside the tetrahedra of cations), except that one-quarter of the anions (oxygen) are missing. The unit cell of these sesquioxides corresponds to eight unit cells of fluorite or cerium dioxide, with 32 cations instead of 4. This is called the bixbyite structure, as it occurs in a mineral of that name (). ==Geological distribution==

The rare-earth elements are found on Earth at similar concentrations to many common transition metals. The most abundant rare-earth element is cerium, which is actually the 25th most abundant element in Earth's crust, having 68 parts per million (more common than copper). The exception is the highly unstable and radioactive promethium "rare earth" that is quite scarce. The longest-lived isotope of promethium has a half-life of 17.7 years, so the element exists in nature in only negligible amounts (approximately 572 g in the entire Earth's crust). Promethium is one of the two elements that do not have stable (non-radioactive) isotopes and are followed by (i.e. with higher atomic number) stable elements (the other being technetium). The rare-earth elements are often found together. During the sequential accretion of the Earth, the dense rare-earth elements were incorporated into the deeper portions of the planet. Early differentiation of molten material largely incorporated the rare earths into mantle rocks. The high field strength and large ionic radii of rare earths make them incompatible with the crystal lattices of most rock-forming minerals, so REE will undergo strong partitioning into a melt phase if one is present. The result is that all magma formed from partial melting will always have greater concentrations of LREE than HREE, and individual minerals may be dominated by either HREE or LREE, depending on which range of ionic radii best fits the crystal lattice. ==Extraction and production==

Rare-earth elements (REEs) are purified from rare-earth oxides (REOs) and mining reserves are quoted in terms of (REO). Terminology deriving from this term includes: • HREO: collective oxides of the heavy rare-earth elements • LREO: collective oxides of the light rare-earth elements Until 1948, most of the world's rare earths were sourced from placer sand deposits in India and Brazil. In the 1950s, South Africa was the world's rare earth source, from a monazite-rich reef at the Steenkampskraal mine in Western Cape province. From the 1960s until the 1980s, the Mountain Pass Rare Earth Mine in California made the United States the leading producer. After China undercut world prices in the 1990s, many mines in other countries closed, and it takes several years to restart production. In 2009, future worldwide demand for rare-earth elements was expected to exceed supply by 40,000 metric tons annually unless major new sources are developed. As a result of the increased demand and tightening restrictions on exports of the metals from China, in 2011, some countries were stockpiling rare-earth resources, Searches for alternative sources continued in many other countries. In 2013, it was stated that the demand for REEs would increase due to the dependence of the EU on these elements, the fact that rare-earth elements cannot be substituted by other elements, and because REEs have a low recycling rate. Due to the increased demand and low supply, future prices were expected to increase. Demand continues to increase due to the fact that they are essential for new and innovative technology. These new products that need REEs to be produced are high-technology equipment such as smartphones, digital cameras, computer parts, semiconductors, etc. In addition, these elements are more prevalent in industries such as renewable energy technology, military equipment, glassmaking, and metallurgy. Increased demand has strained supply, and there has been growing concern that the world may soon face a shortage of the rare earths. As of late 2023, the global demand for rare-earth elements (REEs) was expected to increase more than fivefold by 2030. In 2017, China produced 81% of the world's rare-earth supply, mostly in Inner Mongolia, although it had only 36.7% of reserves. In 2018, Australia was the world's second-largest producer, and the only other major producer, with 15% of world production. The Browns Range mine, located south-east of Halls Creek in northern Western Australia, was under development in 2018, and was positioned to become the first significant dysprosium producer outside of China. As of 2022, all of the world's heavy rare earths (such as dysprosium) were coming from Chinese rare-earth sources, such as the polymetallic Bayan Obo deposit. In 2023, there were over a hundred ongoing mining projects, with many options outside of China. , 85–90% of global rare-earth mineral refining capacity is in China, Production by country The top eight countries in terms of REE reserves, as per the US Geological Survey's February 2025 report on rare-earth elements, are as follows (in tonnes of rare earth oxide equivalent): China In 2009 China announced plans to reduce its export quota to 35,000 tons per year in 2010–2015, ostensibly to conserve scarce resources and protect the environment. It also announced regulations on exports and a crackdown on smuggling. It also suspended rare-earth exports to Japan, due to a dispute over territory. It announced further export quotas in July 2011 for the second half of the year, with total allocation at 30,184 tons and total production capped at 93,800 metric tons. In September 2011, China announced the halt in production of three of its eight major rare-earth mines, responsible for almost 40% of China's total rare-earth production. The United States, Japan, and the European Union filed a joint lawsuit with the WTO in 2012 against China, arguing that China should not be able to deny such important exports. The price of dysprosium oxide was US$994/kg in 2011, and dropped to US$265/kg by 2014. In August 2014, the WTO ruled that China had broken free-trade agreements, and the WTO said in the summary of key findings that "the overall effect of the foreign and domestic restrictions is to encourage domestic extraction and secure preferential use of those materials by Chinese manufacturers." China declared that it would implement the ruling on 26 September 2014, but would need some time to do so. By 5 January 2015, China had lifted all quotas from the export of rare earths, but export licenses were still required. China shut down some of its own ionic clay mines due to their environmental impact, and started mining heavy rare-earths in Myanmar. In 2019, China supplied between 85% and 95% of the global demand for the 17 rare-earth powders, much of it sourced from Myanmar. After the 2021 military coup in that country, future supplies of critical ores were possibly constrained. Between 2020 and 2023, 70% of all rare earth compounds and metals imported into the United States came from China. As of 2025, China was digging up 70 percent of the global supply of rare-earths, but was also processing around 90 of the world supply, refining not only its own ore, but also nearly all of Myanmar's In 2025, during the China–United States trade war, China restricted exports of heavy rare earths to the US. After President Donald Trump imposed high tariffs on American goods being imported by China, in April 2025 China retaliated by imposing restrictions on the sale of seven rare earth minerals to America, and in early October 2025 added further controls. Brazil Brazil has the second-largest reserves of rare-earths in the world, at 23%, but has not produced the metals on a commercial scale until recently. the Brazilian Government is providing nearly $1 billion in funding through the Brazilian Development Bank and the government funding agency Finep. Brazil is seen as a serious challenger to China's dominance of the market. In 2025, a former asbestos mine near the small city of Minaçu began operations to produce the four rare-earths neodymium, praseodymium, dysprosium, and terbium on a commercial scale, the first outside Asia to do this. Serra Verde mining company, which is controlled by American investment fund Denham Capital, began extracting rare-earth minerals in order to export them to China for processing. Mining of the minerals is done in shallow holes, using only water and salt to process the ores. The government-owned Indian Rare Earths is a major player. It was reported in parliament in July 2025 that The country has around 7.23 million tonnes (MT) of REOs contained in 13.15 MT monazite, found in coastal, inland, and riverine sands in the states of Andhra Pradesh, Odisha, Tamil Nadu, Kerala, West Bengal, Jharkhand, Gujarat, and Maharashtra, while another 1.29 MT rare earths are held in hard rocks in parts of Gujarat and Rajasthan. The Atomic Minerals Directorate for Exploration and Research is carrying out exploration in all terrains. The Geological Survey of India has been involved in 34 exploration projects. India exported around 18 tonnes of rare earth minerals between 2015 and 2025. However, India is lacking in advanced REE processing technology and skills, especially compared with China, the US, and Japan, so in 2025 the government launched its "National Critical Mineral Mission", with the aim of developing REE self-reliance. The Ministry of Mines has signed bilateral agreements with several governments around the world, including Australia, Argentina, Zambia, Peru, Zimbabwe, Mozambique, Malawi, and Côte d'Ivoire, as well as with the International Energy Agency. the largest Australian REE companies in terms of stocks are Lynas Corporation; Iluka Resources; Brazilian Rare Earths (whose of mining claims are in the state of Bahia, Brazil); Arafura Rare Earths; and Northern Minerals, whose main development is in Browns Range, Western Australia. Following the publication of its "Critical Minerals Strategy 2023–2030" in June 2023, in November 2024, the Albanese government announced its "International Partnerships in Critical Minerals" program, which will provide AU$40 million in grants across eight projects. The government's Critical Minerals Strategic Reserve plan is due for publication at the end of 2026. The intention of this plan is to introduce mechanisms such as a price floor that bring stability to the market and reduce price volatility. On 21 October 2025, the Prime Minister of Australia, Anthony Albanese, signed a deal with the President of the United States, Donald Trump, A second large deposit of REEs at Elk Creek in southeast Nebraska has been under consideration by NioCorp Development Ltd who hopes to open a niobium, scandium, and titanium mine there. That mine may be able to produce as much as 7,200 metric tons of ferro niobium and 95 metric tons of scandium trioxide annually. As of 2022, financing is still in the works. The Bokan-Dotson Ridge project, the location of a significant deposit of REE, was the subject of a Preliminary Economic Assessment released in January 2013, and was reported by the Alaska Department of Natural Resources to be in an "advanced exploration phase" by Ucore Rare Metals in 2025. However it has no operational capacity. In 2024 American Rare Earths Inc. disclosed that its reserves near Wheatland Wyoming totaled 2.34 billion metric tons, possibly the world's largest, and larger than a separate 1.2 million metric ton deposit in northeastern Wyoming. After China had announced new restrictions on access to their rare-earths in 2025, the U.S. has been seeking alternative supply chains. On 20 October 2025, President Trump signed a deal with the Prime Minister of Australia, Anthony Albanese, that are needed for commercial sustainable energy production and technologically advanced military hardware. They each committed to provide at least US$1bn (A$1.54bn) towards a number of projects worth $US8.5bn (A$13bn) in both the US and Australian projects over six months. Greenland In 2010, a large deposit of rare-earth minerals was discovered in Kvanefjeld in southern Greenland, which is an autonomous territory of Denmark. Pre-feasibility drilling at this site has confirmed significant quantities of black lujavrite, which contains about 1% rare-earth oxides (REO). The European Union has urged Greenland to restrict Chinese development of rare-earth projects there, but as of early 2013, the government of Greenland has said that it has no plans to impose such restrictions. Many Danish politicians have expressed concerns that other nations, including China, could gain influence in thinly populated Greenland, given the number of foreign workers and investment that could come from Chinese companies in the near future because of the law passed December 2012. Tanzania Adding to potential mine sites, Australian Securities Exchange listed Peak Resources announced in February 2012, that their Tanzanian-based Ngualla project contained not only the 6th largest deposit by tonnage outside of China but also the highest grade of rare-earth elements of the 6. South Africa Significant sites under development include Steenkampskraal in South Africa, the world's highest grade rare-earths and thorium mine, closed in 1963, but has been gearing to go back into production. The mine is considered to have the highest-grade ore of monazite in the world, at 50% Total Rare Earth Oxides (TREO). In September 2025 the Industrial Development Corporation (IDC) of South Africa released funding for Phase 1: Metallurgical Implementation. The mine is expected to have a mine life of around 28 years. Canada As of 2006, the remote Hoidas Lake project in northern Canada was being developed. Under consideration for mining are sites such as Thor Lake in the Northwest Territories. Other countries European Union As of 2025, rare earth elements mining is absent in the European Union, with only one operational processing facility owned by the Canadian company Neo Performance Materials. Although REE deposits exist within the EU and European mining companies have begun developing new mines, the permitting processes remain lengthy and financially demanding. The EU member states import practically all of their rare earth elements from China. The European Union Parliament considers this a strategic risk. Japan In May 2012, researchers from two universities in Japan announced that they had discovered rare earths in Ehime Prefecture, Japan. Madagascar A licence to mine rare-earths has been granted to an area covering around a third of the Ampasindava Peninsula on the north-western coast of Madagascar, after a number of exploration-only permits had been issued since 2003. , the licence is held by the Australian company Harena Resources, after changing hands several times. It has been determined that the site contains a defined mineral resource of 699 million tonnes at 868 ppm Total Rare Earth Oxides (TREO), which, according to Harena, makes it one of the largest rare earth deposits in the world. The Kuantan development brought renewed attention to the Malaysian town of Bukit Merah in Perak, where a rare-earth mine operated by a Mitsubishi Chemical subsidiary, Asian Rare Earth, closed in 1994 and left continuing environmental and health concerns. In mid-2011, after protests, Malaysian government restrictions on the Lynas plant were announced. An independent review initiated by the Malaysian Government, and conducted by the International Atomic Energy Agency (IAEA) in 2011 to address concerns of radioactive hazards, found that it was compliant with international radiation safety standards. After several delays, in September 2014 Lynas was issued a two-year full operating stage license by the AELB. In November 2024, economy minister Rafizi Ramli said he hoped Malaysia would be able to produce rare-earth elements within three years, through discussions with China to provide technology. There was some concern in the community about plans to mine rare-earth elements at Kedah, as the mines could destroy forest reserves and harm water catchment areas. Myanmar Rare earths were discovered near Pang War in Chipwi Township along the China–Myanmar border in the late 2010s. China is known to import rare earths from Myanmar (see above). In 2021, China imported of rare earths from Myanmar, exceeding 20,000 metric tons, mostly from Kachin State, after shutting down its own domestic mines due to the detrimental environmental impact. Chinese companies and miners are said to illegally set up operations in Kachin State without government permits, and instead circumvent the central government by working with a Border Guard Force militia under the Tatmadaw, formerly known as the New Democratic Army – Kachin, which has profited from this extractive industry. , there were 2,700 mining collection pools scattered across 300 separate locations found in Kachin State, encompassing the area of Singapore, an exponential increase from 2016. Norway In June 2024, Rare Earths Norway (REN) found a rare-earth oxide deposit of 8.8 million metric tons in Telemark, Norway, making it Europe's largest known rare-earth element deposit. The mining firm predicted that it would finish developing the first stage of mining in 2030. Spain In central Spain, Ciudad Real Province, the proposed rare-earth mining project 'Matamulas' may provide, according to its developers, up to 2,100 Tn/year (33% of the annual UE demand). However, this project has been suspended by regional authorities due to social and environmental concerns. Sweden In January 2023, Swedish state-owned mining company LKAB announced that it had discovered a deposit of over 1 million metric tons of rare earths in the country's Kiruna area, which would make it the largest such deposit in Europe. Ukraine Ukraine holds significant rare earth deposits, which have been at the center of the 2022 Russian invasion of Ukraine and peace negotiations. United Kingdom In the United Kingdom, Pensana has begun construction of their US$195 million rare-earth processing plant which secured funding from the UK government's Automotive Transformation Fund. The plant will process ore from the Longonjo mine in Angola and other sources as they become available. The company are targeting production in late 2023, before ramping up to full capacity in 2024. Pensana aim to produce 12,500 metric tons of separated rare earths, including 4,500 metric tons of magnet metal rare earths. Non-mining REE sources Mine tailings Significant quantities of rare-earth oxides are found in tailings accumulated from 50 years of uranium ore, shale, and loparite mining at Sillamäe, Estonia. Due to the rising prices of rare earths, extraction of these oxides has become economically viable. The country currently exports around 3,000 metric tons per year, representing around 2% of world production. Similar resources are suspected in the western United States, where gold rush-era mines are believed to have discarded large amounts of rare earths, because they had no value at the time. Mining tailings have been found to increase REE enrichment in local soil and water, posing risks to environmental and human health. The research team found a mud layer 2 to 4 meters beneath the seabed with concentrations of up to 0.66% rare-earth oxides. A potential deposit might compare in grade with the ion-absorption-type deposits in southern China that provide the bulk of Chinese REO mine production, which grade in the range of 0.05% to 0.5% REO. Waste and recycling Another recently developed source of rare earths is electronic waste and other wastes that have significant rare-earth components. Advances in recycling technology have made the extraction of rare earths from these materials less expensive. Recycling plants operate in Japan, where an estimated 300,000 tons of rare earths are found in unused electronics. In France, the Rhodia group is setting up two factories, in La Rochelle and Saint-Fons, that will produce 200 tons of rare earths a year from used fluorescent lamps, magnets, and batteries. Coal and coal by-products, such as ash and sludge, are a potential source of critical elements including rare-earth elements (REE) with estimated amounts in the range of 50 million metric tons. ==Uses==

Global consumption The uses, applications, and demand for rare-earth elements have expanded over the years. Globally, most REEs were being used for catalysts and magnets in 2015. Catalysts Lanthanum chloride is used in fluid catalytic cracking for the production of gasoline and diesel. Cerium(III) oxide is used in catalytic converters. Renewables Dysprosium, neodymium, praseodymium, and terbium are key materials for current renewable energy technologies, particularly in electric vehicles (EVs) and wind turbines. EVs use around 1–2 kg (2.2–4.4 lb) of neodymium and praseodymium per vehicle, while wind turbines use up to 600 kg (1,300 lb) of REEs in permanent magnet generators. Iron and glass production and polishing Rare earth metals are used in magnesium alloys, cast iron, and ductile cast irons. Ceria is a key abrasive for fine glass polishing and chemical mechanical planarization. Alloy production, for electronics and other uses Ce, La, and Nd are important in alloy-making, and in the production of fuel cells and nickel-metal hydride batteries. Ce, Ga, and Nd are important in electronics and are used in the production of LCD and plasma screens, fiber optics, and lasers, and in medical imaging. Additional uses for rare-earth elements are as tracers in medical applications, fertilizers, and in water treatment. Geology The application of rare-earth elements to geology is important to understanding the petrological processes of igneous, sedimentary and metamorphic rock formation. In geochemistry, rare-earth elements can be used to infer the petrological mechanisms that have affected a rock due to the subtle atomic size differences between the elements, which causes preferential fractionation of some rare earths relative to others depending on the processes at work. The geochemical study of the REE is not carried out on absolute concentrations – as it is usually done with other chemical elements – but on normalized concentrations in order to observe their serial behaviour. In geochemistry, rare-earth elements are typically presented in normalized "spider" diagrams, in which concentration of rare-earth elements are normalized to a reference standard and are then expressed as the logarithm to the base 10 of the value. Commonly, the rare-earth elements are normalized to chondritic meteorites, as these are believed to be the closest representation of unfractionated Solar System material. However, other normalizing standards can be applied depending on the purpose of the study. Normalization to a standard reference value, especially of a material believed to be unfractionated, allows the observed abundances to be compared to the initial abundances of the element. Normalization also removes the pronounced 'zig-zag' pattern caused by the differences in abundance between even and odd atomic numbers. Normalization is carried out by dividing the analytical concentrations of each element of the series by the concentration of the same element in a given standard, according to the equation: :[\text{REE}_i]_n = \frac{[\text{REE}_i]_\text{sam}}{[\text{REE}_i]_\text{std}} where n indicates the normalized concentration, {[\text{REE}_i]_\text{sam}} the analytical concentration of the element measured in the sample, and {[\text{REE}_i]_\text{ref}} the concentration of the same element in the reference material. It is possible to observe the serial trend of the REE by reporting their normalized concentrations against the atomic number. The trends that are observed in "spider" diagrams are typically referred to as "patterns", which may be diagnostic of petrological processes that have affected the material of interest. Rare-earth elements are also useful for dating rocks, as some radioactive isotopes display long half-lives. Of particular interest are the La-Ce, Sm-Nd, and Lu-Hf systems. REEs are feed additives for livestock which has resulted in increased production such as larger animals and a higher production of eggs and dairy products. This practice has resulted in REE bioaccumulation within livestock and has impacted vegetation and algae growth in these agricultural areas. While no ill effects have been observed at current low concentrations, the effects over the long-term and with accumulation over time are unknown, prompting some calls for more research into their possible effects. ==Issues==

Geopolitical issues ). Import reliance The United States Department of Energy in its 2010 Critical Materials Strategy report identified dysprosium as the element that was most critical in terms of import reliance. Dominance of China China currently has an effective monopoly on the world's REE Value Chain. (All of the refineries and processing plants that transform the raw ore into valuable elements.) In the words of Deng Xiaoping, a Chinese politician from the late 1970s to the late 1980s, "The Middle East has oil; we have rare earths ... it is of extremely important strategic significance; we must be sure to handle the rare earth issue properly and make the fullest use of our country's advantage in rare-earth resources." One possible example of market control is the division of General Motors that deals with miniaturized magnet research, which shut down its US office and moved its entire staff to China in 2006 China's export quota only applies to the metal but not products made from these metals such as magnets. It was reported, but officially denied, that China instituted an export ban on shipments of rare-earth oxides, but not alloys, to Japan on 22 September 2010, in response to the detainment of a Chinese fishing boat captain by the Japanese Coast Guard. China has officially cited resource depletion and environmental concerns as the reasons for a nationwide crackdown on its rare-earth mineral production sector. Non-environmental motives have also been imputed to China's rare-earth policy. A 2011 report "China's Rare-Earth Industry", issued by the US Geological Survey and US Department of the Interior, outlines industry trends within China and examines national policies that may guide the future of the country's production. The report notes that China's lead in the production of rare-earth minerals has accelerated over the past two decades. In 1990, China accounted for only 27% of such minerals. In 2009, world production was 132,000 metric tons; China produced 129,000 of those tons. According to the report, recent patterns suggest that China will slow the export of such materials to the world: "Owing to the increase in domestic demand, the Government has gradually reduced the export quota during the past several years." In 2006, China allowed 47 domestic rare-earth producers and traders and 12 Sino-foreign rare-earth producers to export. Controls have since tightened annually; by 2011, only 22 domestic rare-earth producers and traders and 9 Sino-foreign rare-earth producers were authorized. The government's future policies will likely keep in place strict controls: "According to China's draft rare-earth development plan, annual rare-earth production may be limited to between 130,000 and 140,000 [metric tons] during the period from 2009 to 2015. The export quota for rare-earth products may be about 35,000 [metric tons] and the Government may allow 20 domestic rare-earth producers and traders to export rare earths." A 2025 analysis by Benchmark Mineral Intelligence suggests the West will still be dependent on China for 91% of their heavy rare earths needs by 2030, which is modestly less than 99% in 2024. Mining in the United States The US Bureau of Mines was closed in 1996, which dramatically slowed domestic rare earth mining and research. Import source diversification The United States Geological Survey was actively surveying southern Afghanistan for rare-earth deposits under the protection of United States military forces. Since 2009 the USGS has conducted remote sensing surveys as well as fieldwork to verify Soviet claims that volcanic rocks containing rare-earth metals exist in Helmand Province near the village of Khanashin. The USGS study team has located a sizable area of rocks in the center of an extinct volcano containing light rare-earth elements including cerium and neodymium. It has mapped 1.3 million metric tons of desirable rock, or about ten years of supply at current demand levels. The Pentagon has estimated its value at about $7.4 billion. It has been argued that the geopolitical importance of rare earths has been exaggerated in the literature on the geopolitics of renewable energy, underestimating the power of economic incentives for expanded production. This especially concerns neodymium. Due to its role in permanent magnets used for wind turbines, it has been argued that neodymium will be one of the main objects of geopolitical competition in a world running on renewable energy. But this perspective has been criticized for failing to recognize that most wind turbines have gears and do not use permanent magnets. Generally, it is estimated that extracting 1 metric ton of rare earth element creates around 2,000 metric tons of waste, partly toxic, including 1 ton of radioactive waste. The largest mining site of REEs, Bayan Obo in China produced more than 70,000 tons of radioactive waste, that contaminated ground water. Near mining and industrial sites, the concentrations of REEs can rise to many times the normal background levels. Once in the environment, REEs can leach into the soil where their transport is determined by numerous factors such as erosion, weathering, pH, precipitation, groundwater, etc. Acting much like metals, they can speciate depending on the soil condition being either motile or adsorbed to soil particles. Depending on their bio-availability, REEs can be absorbed into plants and later consumed by humans and animals. Strong acids are used during the extraction process of REEs, which can then leach out into the environment and be transported through water bodies and result in the acidification of aquatic environments. Another additive of REE mining that contributes to REE environmental contamination is cerium oxide (), which is produced during the combustion of diesel and released as exhaust, contributing heavily to soil and water contamination. , 2006 Mining, refining, and recycling of rare earths have serious environmental consequences if not properly managed. Low-level radioactive tailings resulting from the occurrence of thorium and uranium in rare-earth ores present a potential hazard and improper handling of these substances can result in extensive environmental damage. In May 2010, China announced a major, five-month crackdown on illegal mining in order to protect the environment and its resources. This campaign is expected to be concentrated in the South, where mines – commonly small, rural, and illegal operations – are particularly prone to releasing toxic waste into the general water supply. The major operation in Baotou, in Inner Mongolia, where much of the world's rare-earth supply is refined, has caused major environmental damage. China's Ministry of Industry and Information Technology estimated that cleanup costs in Jiangxi province at $5.5 billion. Complications of recycling and reusing REEs Despite the fact that e-waste contains a significant amount of rare-earth elements (REE), only 12.5% of e-waste is currently being recycled for all metals. Main concerns about REE recycling and reuse include environmental pollution during REE recycling and increasing recycling efficiency. Literature published in 2004 suggests that, along with previously established pollution mitigation, a more circular supply chain would help mitigate some of the pollution at the extraction point. This means recycling and reusing REEs that are already in use or reaching the end of their life cycle. A study published in 2014 suggests a method to recycle REEs from waste nickel-metal hydride batteries, demonstrating a recovery rate of 95.16%. Rare-earth elements could also be recovered from industrial wastes with practical potential to reduce environmental and health impacts from mining, waste generation, and imports if known and experimental processes are scaled up. A green system for recovery of REEs from coal fly ash has been developed using citrate and oxalate with strong organic ligands capable of precipitating REEs. A 2019 study suggests that "fulfillment of the circular economy approach could reduce up to 200 times the impact in the climate change category and up to 70 times the cost due to the REE mining." In 2020, in most of the reported studies reviewed by a scientific review, "secondary waste is subjected to chemical and or bioleaching followed by solvent extraction processes for clean separation of REEs." Impact of REE contamination REEs are identified as emerging contaminants under the Environmental Protection Agency's definition "for which a lack of published health standards exist poses a perceived, potential, or real threat to the human health or the environment." There is a sharply increasing number of publications on REE toxicity on plants, animals, and humans in recent years, helping to expand understanding of the complete effects of REEs on health. On vegetation The mining of REEs has caused the contamination of soil and water around production areas, which has impacted vegetation in these areas by decreasing chlorophyll production, which affects photosynthesis and inhibits the growth of the plants. Agricultural plants are the main type of vegetation affected by REE contamination in the environment, with plants like apples and beets having a higher chance of absorbing and storing REEs. In cases of occupational exposure, long term (18 months) inhalation of dust containing high levels (60%) of REEs has been shown to cause pneumoconiosis but the mechanism is unknown. The increase application of REEs in new technologies has increased the need to understand their safe levels of exposure for humans. One side effect of mining REEs can be exposure to harmful radioactive Thorium as has been demonstrated at large mine in Batou (Mongolia). The rare-earth mining and smelting process can release airborne fluoride which will associate with total suspended particles (TSP) to form aerosols that can enter human respiratory systems. Research from Baotou, China shows that the fluoride concentration in the air near REE mines is higher than the limit value from WHO, but the health effects of this exposure are unknown. Analysis of people living near mines in China had many times the levels of REEs in their blood, urine, bone, and hair compared to controls far from mining sites, suggesting possible bioaccumulation of REEs. The elevated presence of REEs was related to the high concentrations in the vegetables the people cultivated, the soil, and the water from the wells caused by the nearby mine.However the levels found were not high enough to cause health effects. Studies indicate potential danger to human and animal health when REE levels exceed accepted background levels in the environment. Affected areas can include the brain, reproductive organs, and gene expression, among others. Lathanum, Cerium, and Neodymium fumes have been shown to be cytotoxic, causing damage to DNA in rats. REEs have been added to feed in livestock to increase their body mass and increase milk production It was also discovered that REEs increase the nutrient use of pigs' digestive systems. Construction of the facility has been halted until an independent United Nations IAEA panel investigation is completed, which is expected by the end of June 2011. New restrictions were announced by the Malaysian government in late June. If the proper safety standards are followed, REE mining is relatively low impact. Molycorp (before going bankrupt) often exceeded environmental regulations to improve its public image. In Greenland, there is a significant dispute on whether to start a new rare-earth mine in Kvanefjeld due to environmental concerns. ==In popular culture==

The plot of Eric Ambler's now-classic 1967 international crime-thriller Dirty Story, aka This Gun for Hire, not to be confused with the 1942 movie This Gun for Hire, features a struggle between two rival mining cartels to control a plot of land in a fictional African country, which contains rich minable rare-earth ore deposits. ==See also==