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Material World
Element · Sc

Scandium

A rare earth in everything but name, whose main use is making aluminium behave like a much better alloy.

Construction material

Scandium is grouped with the rare earths and is not especially rare — it is about as abundant as lead. What makes it scarce commercially is that it almost never concentrates into an ore body of its own, so essentially all production is a by-product of processing something else.

A fraction of a percent of scandium in aluminium refines the grain structure and suppresses the softening that normally happens where welded aluminium meets its heat-affected zone. That is a narrow benefit and an expensive one, which is why scandium-aluminium turns up in bicycle frames and aerospace parts and nowhere cheaper.

Uses

Scandium's uses are few and largely aspirational, held back by supply rather than by merit. Added to aluminium in small amounts it refines the grain structure and produces an alloy that is strong, weldable and light — used in aerospace components and, visibly, in high-end bicycle frames and baseball bats.

Scandium-stabilised zirconia is the best-performing electrolyte for solid oxide fuel cells. Scandium iodide in metal-halide lamps gives a light close to daylight in colour, used where colour rendering matters.

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

is sourced from

  • Titanium — element · from the residues of titanium and uranium processing and from bauxite tailings; no deposit is worked for scandium alone

is produced by

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 Scandium 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

  • Scandium → is sourced from (from the residues of titanium and uranium processing and from bauxite tailings; no deposit is worked for scandium alone) → Titanium → is produced by (as sponge, which must then be crushed, melted and cast before it is usable metal) → Kroll process → takes as input (the inert atmosphere, without which the titanium would take oxygen from the air) → Argon → is produced by (drawn from an intermediate height in the column, between nitrogen and oxygen) → Air separation → takes as input (the feedstock, and an unusual one in being free, unlimited and available anywhere — the cost is entirely the energy to liquefy it) → Air
  • Scandium → is produced by (from the residues of titanium and uranium processing, in quantities small enough that supply is measured in tonnes a year) → Solvent extraction and electrowinning → takes as input (in the low-grade and oxidised ores that flotation cannot economically treat, with bacteria oxidising the sulfide into a form the acid can attack) → Chalcopyrite
  • Scandium → is produced by (from the residues of titanium and uranium processing, in quantities small enough that supply is measured in tonnes a year) → Solvent extraction and electrowinning → takes as input (a carbonate dissolves straight into acid, which is why an oxidised orebody goes to a leach pad and the sulfide beneath it goes to a smelter) → Malachite
  • Scandium → is produced by (from the residues of titanium and uranium processing, in quantities small enough that supply is measured in tonnes a year) → Solvent extraction and electrowinning → takes as input (leached with acid or alkali depending on the host rock, which is what decides the flowsheet of a uranium mill) → Uraninite
  • Scandium → is sourced from (from the residues of titanium and uranium processing and from bauxite tailings; no deposit is worked for scandium alone) → Titanium → is produced by (as sponge, which must then be crushed, melted and cast before it is usable metal) → Kroll process → takes as input (converts the ore to a distillable tetrachloride, which is how the purification is done) → Chlorine → is produced by (at the anode) → Chlor-alkali electrolysis → takes as input (as brine; the salt is the feedstock for both products at once) → Halite
  • Scandium → is sourced from (from the residues of titanium and uranium processing and from bauxite tailings; no deposit is worked for scandium alone) → Titanium → is produced by (as sponge, which must then be crushed, melted and cast before it is usable metal) → Kroll process → takes as input (the reducing agent, recovered afterwards by electrolysing the magnesium chloride by-product) → Magnesium → is produced by (from molten magnesium chloride, including the chloride returned by the Kroll process) → Molten salt electrolysis → takes as input (after concentration, as one of the two routes to lithium chloride) → Lepidolite

These are the most distinct paths back. Scandium can be traced through others besides.

Downstream — what it becomes