Rare Earths 101 : Understanding the Worlds Most Strategic Supply Chain Part 1

Amanda Van Dyke 

 

 

Rare earths are important because of their unique chemistry. They make permanent magnets stronger, lasers sharper, and high powered magnets and electronics smaller and more efficient. From EV motors, fighter jets and missiles to smartphones and GPU’s, they are essential to making modern electronics work. Which is why they are at the centre of some of the fiercest industrial and geopolitical competition of our time.

The name “rare earth” is a bit of a red herring, it makes most people think that relative rarity is the issue, finding mineable deposits. Ironically we have found enough reserves (economically mineable deposits) to mine for the next 100 years. The problem is that not all deposits are created equally, and what is truly rare is not mineable deposits, but “refine-able” deposits. The process of getting the rare earth minerals out of the rock and into a useable form, is in practice, is extremely difficult, messy, chemistry‑intensive, and specific to the quirks of each deposit.

This first part of the series walks through the rare earth value chain from ore to magnet and explains why refining, not mining, is the true bottleneck. The second part will dig into the countries and companies that are attempting to master this bottleneck, and develop independent rare earth value chains, and which are likely to be successful and which not.

What Rare Earths Are – And Why They Matter

The rare earth elements (REE’s), are a set of 17 silvery-white soft metals, the 15 lanthanide elements plus yttrium and scandium. While some are genuinely “rare” some are not. The reason they were called rare is because they often hide in other minerals, and rarely occur in concentrations that are easy to identify, mine and process. Of the 17 rare earths, the crustal abundance varies widely, from 0.28 parts per million (ppm) for thulium to 66 ppm for cerium, to put it in context copper is 60ppm lead is 14ppm, and gold is 0.004ppm.

The Rare Earths

Atomic number, Symbol, Name, Approx. crustal abundance (ppm parts per million in the earths crust)

21 Sc Scandium 22ppm

39 Y Yttrium 30ppm

57 La Lanthanum 31–32ppm

58 Ce Cerium 60–68ppm

59 Pr Praseodymium 7–10ppm

60 Nd Neodymium 27–38ppm

61 Pm Promethium ~0 ppm (no stable abundance)

62 Sm Samarium 4–8ppm

63 Eu Europium 1–2ppm

64 Gd Gadolinium 4–8ppm

65 Tb Terbium ~1ppm

66 Dy Dysprosium 3–6ppm

67 Ho Holmium 0.8–1.4ppm

68 Er Erbium 2–4ppm

69 Tm Thulium ~0.3–0.5ppm

70 Yb Ytterbium 2–3ppm

71 Lu Lutetium ~0.3–0.5ppm

Rare earth element (REE) grades are usually divided into two groups, light rare earths (LREE) and heavy rare earths (HREE). Light rare earths such as lanthanum, cerium, neodymium and praseodymium tend to be more abundant and are used in catalysts, polishing powders and, crucially, high‑performance permanent magnets. Heavy rare earths like dysprosium, samarium and terbium are less abundant but essential for magnets that must operate at high temperatures, for example in electric vehicles or jet engine motors.

What make the rare earths special is their atomic properties, their shielded electron shell configurations that produce sharp, atom‑specific energy levels that drive distinctive magnetic and optical behaviour. In short, the same physics gives you strong magnetism, sharp optical transitions and rich catalytic chemistry – a rare combination in one group of elements.

These metals underpin modern technologies in three main ways:

• Permanent magnets (NdFeB, SmCo) in EV motors, wind turbine generators, industrial drives and defence systems.

• Optical and electronic applications in screens, fibre optics and sensors and GPU’s.

• Catalysts and polishing powders in refining, chemicals and glass manufacture.

Different Types of Rare Earth Deposits

Rare earths almost always occur together with albeit with different distributions in different types of deposits. The rare earths are bound up in different types of minerals/molecules; geologically, there more than 160 known REE‑bearing minerals have been identified, but only a handful – notably bastnäsite, monazite, xenotime, ion‑adsorption clays and a few others – currently form economic ore bodies. In practice, these are grouped into four main deposit types that supply today’s market.”

Carbonatite–bastnäsite deposits
Some of the most important light rare earth deposits are hosted in carbonatite complexes and occur in minerals such as bastnäsite. Famous examples include Mountain Pass in the United States and Bayan Obo in China. These deposits typically have relatively high concentrations of light REEs.

Monazite and xenotime deposits
Monazite and xenotime are phosphate minerals found in hard‑rock deposits and in heavy mineral sands, where rare earths are often recovered as a bi-product. They often carry significant amounts of thorium and sometimes uranium, which creates regulatory and waste management challenges.

Ion‑adsorption clays
The largest of these deposits are found in southern China and neighbouring regions, many heavy rare earths are produced from ion‑adsorption clay deposits formed by weathering of granitic rocks. Here REE ions are loosely bound to clay surfaces rather than locked into robust mineral structures.

Other and emerging sources
There are also rare earths in alkaline igneous complexes, marine sediments, phosphorites and industrial residues such as red mud. Each of these comes with a different mineralogy, impurity suite and physical form, which means no single “universal” flowsheet exists. When people talk about “new” rare earth sources, they are really talking about building new, deposit‑specific refining solutions.

Reserves, Resources and Geopolitical Concentration

Geologists and engineers distinguish between “resources” – the total amount of REEs in the ground that we know about – and “reserves,” which are the portion that can be economically extracted under current conditions. Known resources are approximately 3 times the size of known reserves, and how many will convert to reserves is dependent on a number of factors based on the economics of mining and metallurgy.

Rare earth reserves by country (USGS‑based, ~2026)

Country, Reserves (million t REO), Share of world total (%)

• China 44.0m, ~48.4%

• Brazil 21.0m, ~23.1%

• India 6.9m, ~7.6%

• Australia 5.7m, ~6.3%

• Russia 3.8m, ~4.2%

• Vietnam 3.5m, ~3.9%

• United States 1.9m, ~2.1%

• Greenland, 1.5 m ~1.6%

• Tanzania, 0.89 m, ~1.0%

World total 90.9 million tonnes

From Ore to Concentrate: Beneficiation

The first transformation in the value chain is purely physical. Rare earth ores are crushed and ground into fine particles so that valuable minerals can be separated from waste rock. Because REE minerals typically make up a small fraction of the total rock – often well below ten percent – this stage is about upgrading the ore into a “concentrate” that is rich enough to justify chemical processing.

Typical beneficiation tools include:

• Magnetic and electrostatic separation, exploiting differences in electrical conductivity and magnetic susceptibility between REE minerals and gangue.

• Gravity separation, which distinguishes particles by density.

• Froth flotation, where reagents help target minerals attach to bubbles and float, leaving denser waste behind.

Even at this early stage, the mineralogy of the deposit dictates what works. A flowsheet tuned for bastnäsite will not perform well on monazite, and techniques that look efficient at the laboratory or pilot scale can prove unreliable when confronted with the variability of a real ore body.

Cracking and Leaching: Turning Minerals into Solutions

Once a concentrate is produced, the next challenge is to break open the mineral structures and dissolve the rare earth molecules into solution. This step is often called “cracking,” and it is where the chemical personality of each deposit really begins to dominate.

For monazite and xenotime concentrates, one common route involves digesting the material in concentrated sulfuric acid at high temperature. Colloquially called an “acid bake” or “acid crack”. This attack breaks down the phosphate lattice and liberates rare earths and other elements into a complex mixture. Another route uses caustic soda under pressure to convert the minerals into more soluble forms. Each option has different trade‑offs in terms of recovery, reagent consumption, waste streams and how the thorium and uranium associated with the deposits are handled.

Ion‑adsorption clay deposits behave differently. Because the rare earths are loosely attached to clay surfaces, they can be leached using ammonium sulphate or ammonium nitrate solutions at room temperature. The resulting solutions contain rare earths along with many other dissolved ions and must be further treated to concentrate and purify the target metals.

Carbonatite–bastnäsite concentrates may be roasted, treated with acid or subjected to tailored combinations of physical and chemical steps to remove carbonates and fluorides before leaching. The details matter: temperature, acid strength, solid‑liquid ratios and residence times all influence recovery rates and impurity profiles.

What ties all of this together is that cracking is not a generic recipe. It is a tightly tuned set of conditions that must be discovered and optimised for each deposit through extensive testing and piloting.

Separation Chemistry: Splitting the Rare Earth Cocktail

After cracking and leaching, the rare earths end up in a liquid mixture containing many elements with very similar chemical properties. Separating them into individual products – dysprosium here, neodymium there, cerium in another stream – is one of the most demanding tasks in industrial chemistry.

Most commercial plants use solvent extraction as the backbone of separation. In this process, the leached rare earth solution is mixed with an organic solvent containing special extractant molecules that selectively bind certain rare earths. By carefully controlling pH, temperature and phase ratios, different rare earths are preferentially transferred into the organic phase or left in the aqueous phase. A series of mixer‑settlers or column stages gradually enriches one element in one stream and removes it from others.

Ion exchange techniques are also used, especially to achieve very high purities for optical and electronic applications. Here the solution is passed through resins that bind rare earth ions, which are later stripped off under controlled conditions.

The key point is that these circuits are not simple or uniform. A modern plant may use dozens or even hundreds of stages, each adjusted to the specific composition of feed solutions from its own deposit. Small changes in impurities, acidity or temperature can disrupt performance. As a result, flowsheets developed for one ore body cannot simply be transplanted to another without substantial redesign and testing.

Why rare earths are hard to separate

Rare earths are hard to separate because chemically they are nearly identical. All 15 lanthanides plus yttrium sit in the same column of the periodic table. The only real difference between them is a tiny shrinkage in ionic size going across the series — an effect called lanthanide contraction, the difference is roughly 0.01 angstrom per element. An angstrom is a unit of length equal to one ten-billionth of a metre, or 0.1 nanometres. Neighbouring pairs like neodymium and praseodymium, or dysprosium and holmium, differ in size by less than 1% and behave almost identically in solution. In most of chemistry you separate elements by exploiting big differences in charge, size, or reactivity; with rare earths you have almost none of those to work with, so every step of a separation gives you only a marginal enrichment rather than a clean split.

The workaround is to stack a huge number of those marginal steps into a long cascade. The industry-standard technique is solvent extraction, run in banks of interconnected tanks called mixer settlers. In each tank you stir an aqueous rare-earth solution together with an organic extractant molecule and then the two phases are left to settle apart like oil and water. The aqueous and organic streams flow in opposite directions through the cascade, and the pH is tuned in small increments (0.1–0.2 units at a time) so that at each stage one rare earth is very slightly more inclined to sit in the organic phase than its neighbour. A commercial heavy-rare-earth plant typically runs 60 to 100+ of these tanks in series to peel off a single element at 99.99% purity, and pushing to the 99.999% grade needed for lasers, phosphors and semiconductor parts adds more stages on the back end. The physical operation is not exotic — it is just enormous, slow, reagent-intensive, and unforgiving.

Why impurity removal is almost as hard

Before any of that separation chemistry can even start, the feed has to be cleaned of everything that is not a rare earth, and that pre-cleanup is nearly as demanding as the separation itself. Every deposit brings its own troublesome co-hosts — thorium and uranium in monazite, iron and aluminium in ion-adsorption clay, barium and strontium in bastnaesite — and any of them left in the feed will either crash out inside the mixer-settlers, poison the organic reagent, or contaminate the final oxide. The radioactive impurities are the hardest problem: they force a full tailings and licensing regime around the plant, and are the single biggest reason Western rare-earth projects stall at permitting rather than at chemistry. In practice a rare-earth refinery spends roughly as much of its capital and footprint on the front-end cracking and purification circuit as on the separation cascade itself.

From Oxides to Metals and Alloys

Once separation is complete, producers typically precipitate the rare earths from solution, and then calcine them to form oxides. These oxides – such as neodymium‑praseodymium oxide or dysprosium oxide – are the main traded intermediates and the starting point for making metals and magnet alloys.

Converting oxides into metals involves high‑temperature reduction steps. Common approaches include, metallothermic reduction (smelting), and electrolytic methods, in which oxides or halide salts are reduced in molten salt electrolytes under an electric current.

The resulting metals may be further processed into master alloys, such as NdFeB or SmCo, which form the basis of permanent magnet production. At every stage, impurities like oxygen, carbon or unwanted metals can weaken the final alloy or change its magnetic properties. This makes the quality of upstream refining steps critical for magnet manufacturers.

How Permanent Magnets Are Made – And Why Feed Quality Matters

Rare earth permanent magnets, especially neodymium‑iron‑boron (NdFeB) magnets, are manufactured through carefully controlled metallurgical and microstructural processes. In a typical route, the alloy is melted, rapidly solidified into thin strips, broken down through hydrogen decrepitation, milled into powders and then pressed and sintered into dense shapes under an applied magnetic field. Subsequent heat treatments, machining and protective coatings tune the magnet’s final performance and durability.

Small variations in the composition and purity of rare earth oxides and metals can have outsized effects on magnet performance. For example, adding dysprosium or terbium improves high‑temperature coercivity, but too much or too little can compromise other properties or drive up cost. Excess oxygen, carbon or certain metallic impurities can alter grain structure, reduce remanence or make magnets brittle.

This is why magnet producers place strict specifications on their feedstock and why new rare earth projects must go through extensive qualification before they can supply critical magnet markets. Delivering a concentrate or oxide is not enough; producers must show that their material behaves consistently inside the magnet manufacturing chain.

Why Success in the Lab Rarely Survives the Plant

Looking at this chain – from ore to concentrate, cracking, separation, oxide, metal and magnet – it is tempting to assume that once the basic chemistry is proven in a laboratory, scaling up is only a matter of building larger tanks and pumps. Experience suggests otherwise.

Full‑scale plants must cope with:

• Variable ore feed and changing mineralogy as deposits are mined over time.

• Non‑ideal hydrodynamics, mixing, fouling and corrosion that alter reaction behaviour.

• Supply constraints and price volatility for reagents, energy and water.

• Regulatory and social requirements for handling waste, radioactivity and emissions.

These factors interact in ways bench‑scale tests cannot easily capture. Many projects demonstrate promising recoveries on small samples yet struggle to maintain performance in continuous operation. Tuning the system to be stable and economical at scale becomes a multi‑year process of redesigning circuits, changing reagents, adjusting operating conditions. Basically it is a lot of trial and error.

Companies that are successful in rare earth refining tend to be those that have spent years – sometimes decades – iterating their flowsheets, based on specific deposits, building institutional knowledge and training operators. Their real competitive advantage lies not in a single invention but in thousands of small practical choices about how to make a particular deposit work reliably.

Every Deposit Must Be Qualified

Because rare earth chemistry is so deposit‑specific, each new project faces a double qualification challenge. First, it must demonstrate that it can consistently produce a concentrate material meeting technical specifications – purity, composition, physical form. Second, end‑users must qualify this material in their own processes, whether that is a separation plant, a metals producer or a magnet factory.

This qualification process often takes years and requires large‑scale piloting, detailed testing of product behaviour and long‑term supply agreements. A deposit can look attractive in terms of grade and tonnage yet fail to become a serious supplier if its metallurgy proves too unpredictable or expensive to tame.

Understanding Rare Earths

Understanding rare earths therefore means understanding both the geology and the chemistry. Mines can be developed in a matter of years, but mastering refining is key to any rare earth industrial strategy and the know‑how must be accumulated over much longer cycles. Part II of this series will dig into what it will take to create a rare earth refining industry in the West, and what countries and companies are likely to do it.