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Element · Pr

Praseodymium

A rare earth used to make magnets stronger, glass yellow, and welders' goggles safe to look through.

Praseodymium is a soft, silvery rare earth that develops a green oxide coating in air — the name means green twin, from its separation alongside neodymium from a material once believed to be a single element.

It is almost always found and used together with neodymium, and the two are frequently not separated at all. The mixed praseodymium-neodymium product, known as didymium, is a commercial commodity in its own right, which is a reminder that the rare earths are difficult to separate and often not worth separating.

Uses

Praseodymium's main use is in permanent magnets, where it substitutes for part of the neodymium in neodymium-iron-boron magnets with little loss of performance and some improvement in corrosion resistance. Those magnets drive electric vehicles, wind turbines and hard drives.

Didymium glass absorbs the intense yellow sodium light produced by hot glass, so glassblowers' and welders' goggles use it to let the worker see the piece rather than the glare. Praseodymium also produces a strong yellow ceramic pigment and is alloyed into magnesium for aircraft engine parts.

Medium confidence Weak evidence

How we know: checked recently · only one source, so there is nothing to cross-check it against · stated directly by the source.

How this connects

Where a connection has been confirmed by an outside reference, that reference is named beside it.

is used as

  • Permanent magnets — application · substitutes for part of the neodymium with little loss of performance

is produced by

  • Rare earth separation — process · a light rare earth, separated from its neighbours by countercurrent solvent extraction

is an alternative to

  • Neodymium — element · substitutes for part of the neodymium in a neodymium-iron-boron magnet; the mixed metal is cheaper than separating the two, and the magnet is barely worse for it

is a component of

  • Neodymium magnet — alloy · 0–8% · substituted for part of the neodymium, and usually left in rather than separated out — the two behave nearly identically here and separating them costs money for no benefit
  • Mischmetal — alloy · 3–8% · the rest, and separating it out would cost more than the use requires

Sources

  • Material World
    Our own writing
  • Wikidata
    Wikimedia Foundation · Creative Commons CC0 1.0 Universal (public domain dedication)
  • PubChem
    US National Library of Medicine · Mixed — aggregated third-party content, rights retained by depositors
  • NIST — National Institute of Standards and Technology
    United States Department of Commerce · US Government work — public information, credit requested

Questions this page answers

Where it comes from, and what it becomes

Follow Praseodymium back to what it starts as, and forward into what it becomes. Each step is a documented one — a real route material takes, not a chain of inference.

Upstream — what it comes from

  • Praseodymium → is produced by (a light rare earth, separated from its neighbours by countercurrent solvent extraction) → Rare earth separation → takes as input (the principal ore of the light rare earths, carrying all of them together) → Bastnäsite
  • Praseodymium → is produced by (a light rare earth, separated from its neighbours by countercurrent solvent extraction) → Rare earth separation → takes as input (the other feed alongside bastnäsite, bringing thorium into the residues with it) → Monazite
  • Praseodymium → is produced by (a light rare earth, separated from its neighbours by countercurrent solvent extraction) → Rare earth separation → takes as input (the heavy rare earth feed, where monazite and bastnäsite bring the light ones) → Xenotime

Downstream — what it becomes

  • Praseodymium → is a component of (substituted for part of the neodymium, and usually left in rather than separated out — the two behave nearly identically here and separating them costs money for no benefit) → Neodymium magnet → is used as (the strongest in commercial use, and the reason a motor, a hard drive and an earbud can be small) → Permanent magnets
  • Praseodymium → is a component of (the rest, and separating it out would cost more than the use requires) → Mischmetal → is used as (added to molten steel to scavenge sulfur and oxygen and reshape the inclusions that remain, which improves toughness — an unglamorous use that consumes a great deal of it) → Alloying
  • Praseodymium → is used as (substitutes for part of the neodymium with little loss of performance) → Permanent magnets
  • Praseodymium → is a component of (substituted for part of the neodymium, and usually left in rather than separated out — the two behave nearly identically here and separating them costs money for no benefit) → Neodymium magnet → is used in (direct-drive wind turbine generators, which is what put rare-earth supply into energy policy) → Energy generation
  • Praseodymium → is a component of (the rest, and separating it out would cost more than the use requires) → Mischmetal → is used as (the negative electrode of the nickel-metal hydride battery, which powered hybrid vehicles and portable electronics before lithium-ion displaced it) → Battery electrodes