Tierras raras
https://www.newyorker.com/magazine/2020/04/20/how-anthony-fauci-became-americas-doctor
Geological distribution[edit]
https://en.wikipedia.org/wiki/Rare-earth_element
Production[edit]
Global production 1950–2000
Until 1948, most of the world's rare earths were sourced from placer sand deposits in India and Brazil. Through the 1950s, South Africa was the world's rare-earth source, from a monazite-rich reef at the Steenkampskraal mine in Western Cape province.[36] Through the 1960s until the 1980s, the Mountain Pass rare earth mine in California made the United States the leading producer. Today, the Indian and South African deposits still produce some rare-earth concentrates, but they are dwarfed by the scale of Chinese production. In 2017, China produced 81% of the world's rare-earth supply, mostly in Inner Mongolia,[6][37] although it had only 36.7% of reserves. Australia was the second and only other major producer with 15% of world production.[38] All of the world's heavy rare earths (such as dysprosium) come from Chinese rare-earth sources such as the polymetallic Bayan Obo deposit.[37][39] The Browns Range mine, located 160 km south east of Halls Creek in northern Western Australia, is currently under development and is positioned to become the first significant dysprosium producer outside of China.[40]
Increased demand has strained supply, and there is growing concern that the world may soon face a shortage of the rare earths.[41] In several years from 2009 worldwide demand for rare-earth elements is expected to exceed supply by 40,000 tonnes annually unless major new sources are developed.[42] 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 that REEs have a low recycling rate. Furthermore, due to the increased demand and low supply, future prices are expected to increase and there is a chance that countries other than China will open REE mines.[43] REE is increasing in demand due to the fact that they are essential for new and innovative technology that is being created. These new products that need REEs to be produced are high technology equipment such as smart phones, digital cameras, computer parts, semiconductors, etc. In addition, these elements are more prevalent in the following industries: renewable energy technology, military equipment, glass making, and metallurgy.[44]
China[edit]
See also: Rare earths trade dispute
These concerns have intensified due to the actions of China, the predominant supplier.[45] Specifically, China has announced regulations on exports and a crackdown on smuggling.[46] On September 1, 2009, China announced plans to reduce its export quota to 35,000 tons per year in 2010–2015 to conserve scarce resources and protect the environment.[47] On October 19, 2010, China Daily, citing an unnamed Ministry of Commerce official, reported that China will "further reduce quotas for rare-earth exports by 30 percent at most next year to protect the precious metals from over-exploitation."[48] The government in Beijing further increased its control by forcing smaller, independent miners to merge into state-owned corporations or face closure. At the end of 2010, China announced that the first round of export quotas in 2011 for rare earths would be 14,446 tons, which was a 35% decrease from the previous first round of quotas in 2010.[49] China announced further export quotas on 14 July 2011 for the second half of the year with total allocation at 30,184 tons with total production capped at 93,800 tonnes.[50] 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.[51] In March 2012, the US, EU, and Japan confronted China at WTO about these export and production restrictions. China responded with claims that the restrictions had environmental protection in mind.[52][53] In August 2012, China announced a further 20% reduction in production.[54] The United States, Japan, and the European Union filed a joint lawsuit with the World Trade Organization in 2012 against China, arguing that China should not be able to deny such important exports.[53]
In response to the opening of new mines in other countries (Lynas in Australia and Molycorp in the United States), prices of rare earths dropped.[55] The price of dysprosium oxide was 994 USD/kg in 2011, but dropped to US$265/kg by 2014.[56]
On August 29, 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 September 26, 2014, but would need some time to do so. By January 5, 2015, China had lifted all quotas from the export of rare earths, but export licences will still be required.[57]
In 2019, China supplied between 85% and 95% of the global demand for the 17 rare earth powders, half of them sourced from Myanmar.[58][dubious – discuss] After the 2021 military coup in that country, future supplies of critical ores were possibly constrained. Additionally, it was speculated that the PRC could again reduce rare earth exports to counter-act economic sanctions imposed by the US and EU countries. Rare earth metals serve as crucial materials for EV-manufacturing and high-tech military applications.[59]
Outside China[edit]
As a result of the increased demand and tightening restrictions on exports of the metals from China, some countries are stockpiling rare-earth resources.[60] Searches for alternative sources in Australia, Brazil, Canada, South Africa, Tanzania, Greenland, and the United States are ongoing.[61] Mines in these countries were closed when China undercut world prices in the 1990s, and it will take a few years to restart production as there are many barriers to entry.[46][62] Significant sites under development outside China 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.[63] Over 80% of the infrastructure is already complete.[64] Other mines include the Nolans Project in Central Australia, the Bokan Mountain project in Alaska, the remote Hoidas Lake project in northern Canada,[65] and the Mount Weld project in Australia.[37][62][66] The Hoidas Lake project has the potential to supply about 10% of the $1 billion of REE consumption that occurs in North America every year.[67] Vietnam signed an agreement in October 2010 to supply Japan with rare earths[68] from its northwestern Lai Châu Province.[69]
The largest rare earth deposit in the U.S. is at Mountain Pass, California, sixty miles south of Las Vegas. Originally opened by Molycorp, the deposit has been mined, off and on, since 1951.[37][70] A second large deposit of REEs at Elk Creek in southeast Nebraska[71] is under consideration by NioCorp Development Ltd [72] who hopes to open a niobium, scandium, and titanium mine there.[73] That mine may be able to produce as much as 7200 tonnes of ferro niobium and 95 tonnes of scandium trioxide annually,[74] although, as of 2022, financing is still in the works.[71]
In the UK, Pensana have 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.[75][76] 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 tons of magnet metal rare earths.[77][78]
Also under consideration for mining are sites such as Thor Lake in the Northwest Territories, and various locations in Vietnam.[37][42][79] Additionally, in 2010, a large deposit of rare-earth minerals was discovered in Kvanefjeld in southern Greenland.[80] Pre-feasibility drilling at this site has confirmed significant quantities of black lujavrite, which contains about 1% rare-earth oxides (REO).[81] 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.[82] 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.[83]
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.[84]
Adding to potential mine sites, ASX 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.[85]
North Korea has been reported to have exported rare-earth ore to China, about US$1.88 million worth during May and June 2014.[86][87]
In May 2012, researchers from two universities in Japan announced that they had discovered rare earths in Ehime Prefecture, Japan.[88]
Malaysian refining plans[edit]
In early 2011, Australian mining company Lynas was reported to be "hurrying to finish" a US$230 million rare-earth refinery on the eastern coast of Peninsular Malaysia's industrial port of Kuantan. The plant would refine ore — lanthanides concentrate from the Mount Weld mine in Australia. The ore would be trucked to Fremantle and transported by container ship to Kuantan. Within two years, Lynas was said to expect the refinery to be able to meet nearly a third of the world's demand for rare-earth materials, not counting China.[89] 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.[90][91] In mid-2011, after protests, Malaysian government restrictions on the Lynas plant were announced. At that time, citing subscription-only Dow Jones Newswire reports, a Barrons report said the Lynas investment was $730 million, and the projected share of the global market it would fill put at "about a sixth."[92] 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 no non-compliance with international radiation safety standards.[93]
However, the Malaysian authorities confirmed that as of October 2011, Lynas was not given any permit to import any rare-earth ore into Malaysia. On February 2, 2012, the Malaysian AELB (Atomic Energy Licensing Board) recommended that Lynas be issued a temporary operating license subject to meeting a number of conditions. On 2 September 2014, Lynas was issued a 2-year full operating stage license by the AELB.[94]
Other sources[edit]
Mine tailings[edit]
Significant quantities of rare-earth oxides are found in tailings accumulated from 50 years of uranium ore, shale and loparite mining at Sillamäe, Estonia.[95] Due to the rising prices of rare earths, extraction of these oxides has become economically viable. The country currently exports around 3,000 tonnes per year, representing around 2% of world production.[96] 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.[97]
Ocean mining[edit]
In January 2013 a Japanese deep-sea research vessel obtained seven deep-sea mud core samples from the Pacific Ocean seafloor at 5,600 to 5,800 meters depth, approximately 250 kilometres (160 mi) south of the island of Minami-Tori-Shima.[98] 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.[99][100]
Waste[edit]
Another recently developed source of rare earths is electronic waste and other wastes that have significant rare-earth components.[101] Advances in recycling technology have made extraction of rare earths from these materials less expensive.[102] Recycling plants operate in Japan, where an estimated 300,000 tons of rare earths are found in unused electronics.[103] 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.[104][105] Coal and coal by-products are a potential source of critical elements including rare earth elements (REE) with estimated amounts in the range of 50 million metric tons.[106]
Methods[edit]
One study mixed fly ash with carbon black and then sent a 1-second current pulse through the mixture, heating it to 3,000 °C (5,430 °F). The fly ash contains microscopic bits of glass that encapsulate the metals. The heats shatters the glass, exposing the rare earths. Flash heating also converts phosphates into oxides, which are more soluble and extractable. Using hydrochloric acid at concentrations less than 1% of conventional methods, the process extracted twice as much material.[107]
Properties[edit]
According to chemistry professor Andrea Sella, 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.[3] 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."[3]
Uses[edit]
Global REE consumption, 2015[108]
Catalysts, 24% (24%)
Magnets, 23% (23%)
Polishing, 12% (12%)
"other", 9% (9%)
Metallurgy, 8% (8%)
Batteries, 8% (8%)
Glass, 7% (7%)
Ceramics, 6% (6%)
Phosphors and pigments, 3% (3%)
US consumption of REE, 2018[109]
Catalysts, 60% (60%)
Ceramics and glass, 15% (15%)
Polishing, 10% (10%)
"other", 5% (5%)
Metallurgy, 10% (10%)
The uses, applications, and demand for rare-earth elements has expanded over the years. Globally, most REEs are used for catalysts and magnets.[108] In USA, more than half of REEs are used for catalysts, and ceramics, glass and polishing are also main uses.[109]
Other important uses of rare-earth elements are applicable to the production of high-performance magnets, alloys, glasses, and electronics. Ce and La are important as catalysts, and are used for petroleum refining and as diesel additives. Nd is important in magnet production in traditional and low-carbon technologies. Rare-earth elements in this category are used in the electric motors of hybrid and electric vehicles, generators in wind turbines, hard disc drives, portable electronics, microphones, speakers.[citation needed]
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, lasers,[110] as well as in medical imaging. Additional uses for rare-earth elements are as tracers in medical applications, fertilizers, and in water treatment.[25]
REEs have been used in agriculture to increase plant growth, productivity, and stress resistance seemingly without negative effects for human and animal consumption. REEs are used in agriculture through REE-enriched fertilizers which is a widely used practice in China.[111] In addition, 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. However, this practice has resulted in REE bio-accumulation within livestock and has impacted vegetation and algae growth in these agricultural areas.[112] Additionally 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.[111][113]
Given the limited supply, industries directly compete with each other for resources, e.g. the electronics sector is in direct competition with renewable energy use in windfarms, solar panels and batteries.[114]
Environmental considerations[edit]
REEs are naturally found in very low concentration in the environment. Mines are often in countries where environmental and social standards are very low, leading to human rights violations, deforestation and contamination of land and water.[114][115]
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, ground water, 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. The mining of REEs, use of REE-enriched fertilizers, and the production of phosphorus fertilizers all contribute to REE contamination.[116] Furthermore, strong acids are used during the extraction process of REEs, which can then leach out in to 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 (CeO
2), which is produced during the combustion of diesel and released as exhaust, contributing heavily to soil and water contamination.[112]
False-color satellite image of the Bayan Obo Mining District, 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 element ores present a potential hazard[117] 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,[118] where mines – commonly small, rural, and illegal operations – are particularly prone to releasing toxic waste into the general water supply.[37][119] However, even the major operation in Baotou, in Inner Mongolia, where much of the world's rare-earth supply is refined, has caused major environmental damage.[120] China's Ministry of Industry and Information Technology estimated that cleanup costs in Jiangxi province at $5.5 billion.[115]
It is, however, possible to filter out and recover any rare earth elements that flow out with the wastewater from mining facilities. However, such filtering and recovery equipment may not always be present on the outlets carrying the wastewater.[121][122][123]
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