Factsheet: All about the rare earth metals that sent the world trade into a tizzy

Beijing's near-complete control over these metals has left countries scrambling to secure alternative supplies. According to Reuters, India has even asked its state-run miner to pause a long-standing export deal with Japan, with an aim to preserve the key metals for domestic use and reduce dependence on China.

But what are these metals, how widespread are they around us, and why are they described as ‘rare’? Let’s look at the significance of rare earth metals.

What are rare earth metals?

Rare earth metals, or rare earth elements (REEs), or simply rare earths, are a group of 17 metals found in the middle of the periodic table that you might recall from chemistry class at school. These have atomic numbers 21, 39, and 57–71. They are characterized by special magnetic, light-emitting, and conductive properties that make them valuable when alloyed or added in small amounts to common metals such as iron. Scroll down further to see the full list of these elements.

Also Read: India’s EV dreams are caught between rare earth and a hard place

Why are they called so?

Unlike what their name suggests, REEs are fairly abundant in the Earth's crust. But due to certain unique geochemical characteristics, they tend to be spread out rather than concentrated. That means their deposits are often not dense enough to allow economical extraction. Extracting a usable quantity from an ore needs a lot of energy and environmentally unfriendly chemicals. These challenges earned them the name "rare earths".

What makes rare earth metals special?

F-electrons are a set of electrons found just beneath the outer layer of atoms of REEs. They play a key role in giving these metals their strong magnetic properties and the ability to glow. All this makes REEs useful in items such as magnets, lights, and screens. 

Also Read: China’s rare earth export curbs are India’s wake-up call

Why is mining rare earths risky?

Mining rare earth metals isn't just expensive; it's also environmentally hazardous. 

They are often found mixed with radioactive elements such as uranium and thorium. The two common methods used to mine them involve a "leeching pond", an artificial water pit in which rare earths are extracted with the help of carcinogenic toxins (e.g. sulphates, ammonia and hydrochloric acid). These leeching ponds, if not fully isolated, can leak and contaminate groundwater and waterways.

How did China gain monopoly over rare earth metals?

Cheaper production, relaxed environmental rules, and access to rare earth-rich regions helped China become a global leader. Starting in the 1980s, China developed deep expertise in extraction and processing rare earth metals. Since the 1990s, China has dominated production, driven by low prices and heavy state investment in infrastructure and technology. So much so, the US, once a leader in rare earth extraction, now sends its own mined metals to China for processing and refinement.

Also Read: China risks overplaying its hand by curbing rare earth exports

Here’s the full list of the 17 rare earth elements, along with their year of discovery, symbol, atomic number, and key uses, sourced from the US Geological Survey.

 

Here’s the full list of the 17 rare earth elements, along with their year of discovery, symbol, atomic number, and key uses, sourced from the US Geological Survey.

• Scandium, Sc (Atomic number: 21) - Discovered: 1791

Used in super alloys, ultra-light aerospace components, X-ray tubes, baseball bats, lights, semiconductors

• Yttrium, Y (39) - 1794

Ceramics, metal alloys, rechargeable batteries, TV phosphors, high-temperature superconductors

• Lanthanum, La (57) - 1839

Batteries, optical glass, camera lenses, petroleum refining catalysts

• Cerium, Ce (58) - 1803

Catalysts, metal alloys, radiation shielding, water purifier

• Praseodymium, Pr (59) - 1885

Magnets, lasers, pigments, cryogenic refrigerant

• Neodymium, Nd (60) - 1885

High-strength permanent magnets, lasers, infrared filters, hard disc drives

• Promethium, Pm (61) - 1945

Batteries, lighting, instruments

• Samarium, Sm (62) - 1879

High temperature magnets, nuclear reactor control rods and shielding, lasers, microwave filters

• Europium, Eu (63) - 1901

LCDs, fluorescent lighting, red and blue phosphors

• Gadolinium, Gd (64) - 1880

MRI contrast agent, memory chips, nuclear reactor shielding, CDs

• Terbium, Tb (65) - 1843

Green phosphors, lasers, fluorescent lamps, optical computer memories

• Dysprosium, Dy (66) - 1886

Permanent magnets, lasers, catalysts, nuclear reactors

• Holmium, Ho (67) - 1867

Lasers, nuclear reactors, catalysts, magnets

• Erbium, Er (68) - 1842

Lasers, vanadium steel, infrared absorbing glasses, optical fibres

• Thulium, Tm (69) - 1879

Portable X-ray machines, microwaves,

• Ytterbium, Yb (70) - 1878

Infrared lasers, chemical reducing agent, rechargeable batteries, fibre optics

• Lutetium, Lu (71) - 1907

PET scan detectors, superconductors, high refractive index glass, x-ray phosphor