Rare earths are a set of elements that have an incredible degree of importance in the modern world. I want to go over and make mentally digestible to a layman the subject in general, and demonstrate how China managed to become the top leader in their mining and processing, and what this may mean going forward as we enter the New Cold War.
I’m going to split this into two parts: the first part will be about what rare earth elements (REEs) actually are, and how they’re mined and processed. This isn’t strictly necessarily for understanding the second part, which is how the industry has evolved, so I’ve put the first part in the comments for you to read if you so desire.
Also, if you wanna read the whole thing in one go rather than it being segmented across a bunch of comments, then I've put this on the site.
How Did The Rare Earth Industry Develop, and How Did China Conquer It?
Part 1.
So, you either read the introduction in the comments and know what an REE is, or you didn’t because you already have the basic idea that these are some important magic metals which countries need to make things that are technologically advanced, which is really all that’s important if you’re not interested in geology. Onwards!
While we could begin centuries ago with their discovery, I will skip past all the initial discoverers as it’s not really relevant to us. Instead, the story will begin - kind of - in the 1960s. Before this time, only about 2000 tons of REEs were produced every year, and these were mostly sourced from monazite and xenotime ores - two of the big three REE ores, if you didn’t read the introduction - and it was discovered in this decade that europium had properties that advanced the development of cathode ray tubes inside color televisions.
In 1964, the Mountain Pass mine in California began to be exploited, a source of bastnaesite ore (the third of the big three ores, and the most important REE ore today). The Mountain Pass mine was initially designed to extract europium, but other REEs were extracted with time, and with larger quantities to work with than previous, obscure sources, scientists could research their properties and find uses for them. This mine was the dominant source of light REEs (that is, the REEs on the left side of the lanthanide group, and much more common than the heavy REEs) in the West until the 1990s, and was owned by Molycorp.
However, in the 1980s, China entered the scene.
In 1986, Deng Xiaoping approved Program 863: The National High Technology Research and Development Program. This program focused on biotechnology, space, information, laser, automation, energy, and material science, and the objective of it was to close the gap between China and the rest of the world and achieve a strategic foothold. REEs were a part of each scientific area that Program 863 focused on - the potential value of these elements was very apparent to the Chinese scientific leadership. In 1997, China’s Ministry of Science and Technology introduced Program 973, which is the largest basic research program in China. Research projects inside this program could last five years and receive money on the order of a couple million dollars. These two programs were not the only programs relating to REEs, but they are by far the two most important ones.
To cover how China managed to acquire its REEs, we’ll need to go back to 1927. At this time, a geologist discovered iron deposits at a location called Bayan Obo in Inner Mongolia, China - and seven years later, the presence of bastnaesite and monazite was discovered too. In the 1950s, exploitation of the mine began for both iron and REEs. At this time, of course, there were few uses for REEs and so they were not particularly commercially exciting - but the iron ore mined here was, and provided the income necessary to keep extracting the REEs alongside the iron.
One of the key figures around this time was Xu Guangxian, who is regarded as the father of Chinese REE chemistry. Achieving a Ph.D. in chemistry in the United States and then returning to China after the outbreak of the Korean War, he went to work at Peking University. He initially researched metal extraction, and then in 1956 switched to radiation chemistry and the extraction of nuclear fuels, helping China eventually develop nuclear weapons. After the Cultural Revolution began in 1966, Xu turned to theoretical research, and then was accused of being a spy for the Kuomintang and imprisoned until 1972, after which he was released and returned to developing REE extraction methods, using what he learned from extracting uranium isotopes. In the 1990s, he chaired the chemistry sector of the National Natural Science Foundation. By 1999 he was still unsatisfied with Chinese REE development, and continued to push the industry hard. In 2009, he won the State Supreme Science and Technology prize, the Chinese equivalent to the Nobel Prize. He died at the age 94 in 2015. He was a steadfast supporter of the importance of the field of chemistry, despite it appearing to many STEM students as merely an accompanying field to the more exciting field of physics.
Back to the late 20th century. Global consumption of REEs was synergistic with Chinese production and research into their properties. Between 1978 and 1989, China increased its production by an average of 40% every year. As their production grew and Chinese REEs flooded the market, the profits that other countries could gain from REEs plunged, and in the 1990s, Western mines substantially reduced production or shut down entirely. In 1992, Deng Xiaoping proclaimed “There is oil in the Middle East; there is rare earth in China.” Seven years later, President Jiang Zemin wrote “Improve the development and application of rare earth, and change the resource advantage into economic superiority.”
Xu Guangxian established two state laboratories in China, both of which focus on REEs; the State Key Laboratory of Rare Earth Materials Chemistry and Applications in Peking University, Beijing; and the State Key Laboratory of Rare Earth Resource Utilization in Changchun. There are two other REE-dedicated laboratories in China: the Baotou Research Institute of Rare Earths, the largest rare earth research and development institution in the world; and the General Research Institute of Nonferrous Metals (though this one is, as the name suggests, not exclusively focused on REEs). Each of the four laboratories focuses on a different aspect of REEs. One focuses on applied research, one on basic research, and two on industrial applied research. There are additionally two publications dedicated to REEs: the Journal of Rare Earth and the China Rare Earth Information journal.
Chinese mines have also advanced beyond Bayan Obo, with other REE deposits exploited in Baotou, Shangdong, Jiangxi, Guangdong, Hunan, Guangxi, Fujian, and Sichuan, to name a few places.
China faced, and still faces, two major problems with REE production: it’s tremendously environmentally damaging, and production by illegal companies and smuggling disrupts markets.
According to the Chinese Society of Rare Earths, for every ton of REE produced: approximately 8.5 kilograms of fluorine and 13 kilograms of dust; approximately 10,000 cubic meters of waste gas including various acidic substances; 75 cubic meters of acidic wastewater; and one ton of radioactive waste residue, is produced. The water runoff contaminates the surrounding area and irrigated farmlands. One ton of REE also produces 2000 tons of mine tailings, which are the ground up rock left behind from mining it, which often contains radioactive thorium. These figures may have improved as years have gone by, but the environmental impact is still large to this day. Xu Guangxian wrote in 2005 of the consequences of this thorium entering the water in the local area and the Yellow River, upon which hundreds of millions of people depend.
In 2008, about 20,000 tons of REE minerals were smuggled out of the country; compare this to official production of 40,000 tons. The lack of control over the smugglers means that prices are kept low and illegal companies have even less concern for environmental impacts. China’s development plans in this field have routinely focused on introducing regulations and policies to combat smugglers. I have been unable to find decent figures for the current state of illegal mining in China, although this Reuters article from 2019 suggests that the crackdowns continue.
What is a Rare Earth Element?
There are 17 elements that are classified as REEs; these are scandium, ytterium, and the whole Lanthanide Group: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. These are all generally stable and nonradioactive elements, aside from promethium. Yttrium, despite not being a lanthanide, has very similar properties and so is grouped in. Scandium is actually more similar to the ferromagnesian elements - think iron and nickel - but in some circumstances it behaves a lot like an REE, so it gets to join the club.
The reason they’re called “rare earth elements” is due to the circumstances of their discovery. The only place in the world where they could be found in the 19th century was a town called Ytterby in Sweden, thus making them rare, and in French, an oxide of an element is called the “terre” or earth of that element, and these elements were found as oxide minerals. However, since then, we’ve found that some of these elements, such as cerium, are actually more common than lead in the Earth’s crust - and even the rarest ones, like lutetium, are orders of magnitude more common than gold.
REEs tend to have quite high ionic radii, which makes them difficult to fit into minerals when they’re forming when magma cools - in the business, this is a property called incompatibility. This means that as a magma cools down, such as in a magma chamber or some kind of intrusion near the surface, the parts that solidify and form mineral crystals first “reject” the REEs, kinda like unpopular kids not being picked for sports teams in school by team captains, leaving them behind in the remaining liquid rock. This continues until eventually a forming rock is “forced” to pick them up - there’s no other players for the team captains to choose for their teams.
The type of rock that forms at the end of this process is called a pegmatite. You might see the “ite” at the end and conclude that it’s a mineral with some kind of chemical formula, like other minerals like “calcite”, but it’s actually purely a description of texture - pegmatites are defined as being coarse-grained and having large crystals of a certain minimum size. Ytterby, the first mine that REEs were found in was, correspondingly, a granite pegmatite.
The Minerals
The principal minerals that REEs are found in are monazite, bastnaesite, xenotime, and eudialyte. These minerals actually do have chemical formulas - and if you’re curious, two of them are phosphate minerals - but all you need to know as a layman is that these are the main minerals which contain a range of REEs.
Monazite was the first one to be exploited, and typically contains a mixture of Light Rare Earth Elements (LREEs), which are the ones found on the left side of the lanthanides. However, it’s quite a heavy mineral, about twice as dense as a general granite, and resistant to weathering, so it tends to separate out from other minerals in the granite and concentrate into placers - which may be a familiar term if you know about the gold rushes a couple centuries ago.
Bastnaesite also tends to contain LREEs, though it does also have significant amounts of yttrium and small amounts of HREEs (the right side of the lanthanides). In the modern day, bastnaesite has taken monazite’s throne as the primary LREE ore. It’s widespread but doesn’t occur in large quantities, and occurs in a greater variety of rocks than just pegmatites, such as carbonatites (igneous rocks that have a lot of carbonate minerals; imagine melting and resolidifying limestone and chalk).
Xenotime contain a relatively larger proportion of HREEs. It forms in pegmatites and also metamorphic rocks - which is the rock class in between sedimentary and igneous rocks that have been “cooked” to high temperatures but not completely melted and reformed by heat and pressure, giving them interesting properties and appearances that we don’t have time to talk about.
Eudialyte is easily dissolvable in acid and tend to be sources of other elements, like zirconium, but also contain some REEs.
There are numerous other minor minerals that contain one or two REEs, but it is typically not economical at this time to extract them.
What are they used for?
There’s no way that I can be comprehensive nor particularly detailed with this list or we’d be here all day, but I’ll go through each element in turn and give a few interesting things that they’re used in. Feel free to skip this part.
List of uses
Scandium: mainly used to make aluminium alloys. One isotope (essentially a different version of that element with a different number of neutrons, these tend to be at least somewhat radioactive but not always) is used in oil refineries. Sometimes used in lightbulbs and lights.
Yttrium: many uses: it’s used in alloys, color television and monitor displays, camera lenses, superconductors, and magnetic recording.
Lanthanum: an abundant REE, it’s always used in alloys, e.g. for battery alternative metals, catalysts for the petroleum industry, optical glasses, and superconductors.
Cerium: another abundant REE, cerium oxide is widely used for polishing, for catalysts like lanthanum, for catalytic convertors, and for red pigments.
Praseodymium: alloying metal for the aircraft industry, pigments, glasses for welding, and some optical fibres.
Neodymium: probably the most famous REE of them all, it makes very strong permanent magnets, which are used in essentially everything that you can imagine which uses modern technology.
Promethium: a very radioactive element, it’s used basically entirely in research.
Samarium: can be combined with cobalt to make high strength magnets that work at high temperatures and are resistant to corrosion.
Europium: it’s main feature is its phosphorescence, and so used to be used in color televisions and monitors a lot, but nowadays has been superseded by other elements in many cases.
Gadolinium: has a lot of specialized uses, but none that are large scale. Used in nuclear reactor shielding, MRI scanning, and some alloys.
Terbium: used for chemical doping for some compounds, used in some luminescent materials, as well as alongside zirconium oxide for fuel cells.
Dysprosium: added often to neodymium magnets. Also used for cooling nuclear reactor rods.
Holmium: has the highest magnetic field of any element, so tends to be used for magnetic purposes.
Erbium: used as a photographic filter, safety goggles, optical fibers, and lasers.
Thulium: few applications due to its cost and rarity; sometimes used in dopants and lasers.
Ytterbium: few applications due to its cost and rarity, sometimes used to strengthen steel and as an industrial catalyst
Lutetium: rarest REE, sometimes used as a beta particle emitter, in bubble memory when that was a thing, and PET scanners.
The Balance Problem
I couldn’t find a place to put this section in the main narrative but it’s worth mentioning.
The “balance problem” is essentially just the observation that because not all REEs are used equally - for example, the big superstar is neodymium, with others of similar abundance not used quite as much - and because ores containing REEs often will contain a mixture of lots of different REEs, then you inevitably end up with a situation where you’re stockpiling the less used elements in larger and larger quantities as the most used ones get traded away. The price of stockpiling these excess REEs goes up and up and the market price for them goes down as supply increases, and because a mining company must (under capitalist logic) make a profit, this introduces a pressure that makes them not want to mine as much ore (due to stockpiling costs) but simultaneously need to mine more ore (because often the minor elements are what the world economy needs more of), so it’s difficult to achieve an overall balanced market.
There are five proposed solutions to the problem:
Find uses for the elements that aren’t used very much.
Find substitutions for elements that are used a lot.
Mine ores outside of the big three of monazite, bastnaesite, and xenotime that contain only one or two REEs (but this is, under capitalism, less economically feasible, and even not under capitalism, still introduces big environmental concerns to other places)
Recycle REEs more.
Reduce their use as much as possible by using them more efficiently.