Rare Earth Elements – The Metals Hiding in Everything

There are seventeen elements collectively called the rare earths: the fifteen lanthanides, plus scandium and yttrium. They have unfamiliar names — neodymium, dysprosium, praseodymium, europium — and they are in almost every piece of technology you own.

They are not actually rare

The name is a historical accident. Cerium is more abundant in the earth’s crust than copper. Neodymium is more common than tin. Even thulium, one of the scarcer ones, is more abundant than gold.

What makes them difficult is that they are diffuse. They do not concentrate into rich ore bodies the way copper or lead do. They occur thinly spread, mixed together, and — this is the real problem — they are chemically almost identical to one another.

The lanthanides share the same outer electron configuration and differ only in how many electrons occupy an inner shell. Chemistry is largely governed by outer electrons, so these elements behave in nearly the same way. Separating them means exploiting very small differences over and over, through hundreds of stages of solvent extraction. It is one of the more tedious industrial processes ever devised.

What that inner shell buys us

The buried electrons that make the rare earths hard to separate are exactly what make them useful.

In most atoms, the outer electrons interact strongly with their surroundings, which smears out their magnetic and optical properties. In the lanthanides, the relevant electrons are shielded by outer shells, so they behave almost as though the surrounding material were not there.

This produces two remarkable effects. The magnetic moments stay aligned and enormous, giving us the strongest permanent magnets ever made. And the optical transitions stay extremely sharp, producing pure, precise colours of emitted light rather than broad smears.

Where they turn up

Neodymium, usually alloyed with iron and boron, makes the magnets in headphones, phone speakers, hard drive actuators, electric vehicle motors and wind turbine generators. A modern electric car contains a couple of kilograms of rare earth magnets. Dysprosium is added because neodymium magnets lose their strength when hot, and dysprosium raises the temperature at which that happens.

Europium and terbium produce the red and green in displays and fluorescent lighting. Erbium amplifies light in the optical fibres carrying essentially all intercontinental internet traffic — every message you send overseas is boosted along the way by erbium atoms. Cerium is used to polish glass, including phone screens and optical lenses. Lanthanum sits in the catalysts that refine petroleum.

The supply problem

Because separation is difficult, capital-intensive and environmentally demanding, the processing capacity is heavily concentrated in a small number of countries — overwhelmingly China, which handles the majority of global refining regardless of where the ore was mined.

Australia has significant deposits and is a substantial miner of rare earth ore, but for a long time sent most of it offshore for processing. That is changing, and it is a strategically interesting question for a country with the geology but historically not the refining industry.

There is also a genuine environmental cost. Rare earth ores frequently contain thorium and uranium, so processing generates radioactive tailings that require long-term management. This is a real constraint, not a rhetorical one.

The recycling question

Given the difficulty of extraction, recovering these elements from discarded technology ought to be obvious. In practice, recycling rates for rare earths have been very low — historically only a few per cent.

The reason is that they are used in tiny quantities, dispersed through complex assemblies, alloyed with other metals and glued into place. Recovering a few grams of neodymium from a hard drive means dismantling the drive, finding the magnet, and separating it from the iron and boron it is alloyed with.

This is improving as the economics shift and as processes designed for the purpose replace processes borrowed from other metals. It is also one of the better arguments for taking equipment disposal seriously — a business sending old laptops and drives through a properly documented IT asset disposal process is feeding material into a recovery chain, whereas the same equipment in landfill takes its dysprosium with it.

Why they are worth knowing about

The rare earths sit at an unusual intersection: chemically obscure, industrially essential, geopolitically sensitive and almost entirely invisible to the people who depend on them. Every time a phone vibrates, a hard drive seeks, or a wind turbine turns, it is doing so because of an electron shell buried deep inside an atom most people have never heard of.