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Element · Co

Cobalt

A blue pigment for three thousand years, a battery cathode today, and a supply chain concentrated in one country.

Pigment

Cobalt has coloured glass and ceramics blue since antiquity, long before it was recognised as an element. Its modern significance is different: cobalt stabilises the cathode structure of lithium-ion batteries, and superalloys containing it retain strength at the temperatures inside a jet engine.

More than two thirds of world supply comes from the Democratic Republic of the Congo, much of it as a by-product of copper mining. That concentration, and the artisanal mining conditions associated with part of it, has made cobalt reduction an explicit design goal for battery manufacturers.

Name origin

From German Kobold, a goblin — miners' name for an ore that looked like silver, yielded none, and released poisonous arsenic fumes when smelted.

Uses

Cobalt's modern importance is the lithium-ion battery, where it stabilises the cathode structure through repeated charge cycles. That single use has reshaped its market and drawn attention to its supply, much of which comes from the Democratic Republic of the Congo under conditions that have been widely criticised.

Older uses continue: cobalt superalloys hold their strength in jet engine hot sections, cobalt carbide binds tungsten carbide cutting tools, and cobalt compounds give the deep blue of glass and ceramic glaze.

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 sourced from

  • Copper — element · much of world supply arrives as a by-product of copper mining rather than from cobalt-first operations

is used as

  • Battery electrodes — application · stabilises the cathode structure
  • Pigment — application · cobalt blue, in use for three thousand years

is extracted from

  • Cobaltite — mineral · a cobalt ore, though most cobalt now arrives as a by-product of copper and nickel mining Wikidata

is produced by

  • Smelting — process · generally alongside copper or nickel rather than from a cobalt-first operation
  • Solvent extraction and electrowinning — process · from the copper belt of central Africa, where cobalt follows copper into the leach solution and is separated from it downstream

is an alternative to

  • Nickel — element · in battery cathodes, where nickel-rich chemistries were developed specifically to use less cobalt — a substitution driven by the conditions cobalt is mined under as much as by its price

is a component of

  • Samarium–cobalt magnet — alloy · 60–80% · the balance, and both the reason it works hot and the reason it is expensive
  • Nickel superalloy — alloy · 5–15% · a substantial addition, and one of the reasons aviation and battery demand compete for the same metal

is found in

  • High-speed steel — alloy · 0–12% · raises hot hardness further, in the grades used for the most demanding cutting
  • Cobalt-chromium alloy — alloy · 55–70% · the balance
  • NMC cathode — compound · the structural stabiliser that keeps nickel out of the lithium layer, and the element the last fifteen years of development has been trying to use less of
  • Lithium cobalt oxide — compound · roughly a third by mass, which is why nothing with a large pack uses it
  • Cobaltite — mineral Wikidata

is used in

  • Lithium-ion cell — object · in the cathode of the older chemistries, and the component the industry has been designing away from
  • Stained glass window — object · the blue, at concentrations low enough that a very little went a very long way and was traded accordingly
  • Smartphone — object · the cathode, and the element carrying the supply problem no audit has closed

is a source for

  • NMC cathode — compound · roughly seventy per cent of it mined in the Democratic Republic of the Congo and refined overwhelmingly in China, which is the concentration the whole low-cobalt programme is a response to
  • Lithium cobalt oxide — compound · and a phone battery is a meaningful cobalt consumer per unit of energy stored, which the tonnages hide because the cells are small

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 Cobalt 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

  • Cobalt → is sourced from (much of world supply arrives as a by-product of copper mining rather than from cobalt-first operations) → Copper → is produced by (as blister copper, refined electrolytically afterwards) → Smelting → takes as input (as the element removed, not added) → Oxygen → is produced by (the largest output by tonnage, and the reason air separation units sit beside steelworks) → 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
  • Cobalt → is produced by (generally alongside copper or nickel rather than from a cobalt-first operation) → Smelting → takes as input (as the element removed, not added) → Oxygen → is produced by (the largest output by tonnage, and the reason air separation units sit beside steelworks) → 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
  • Cobalt → is produced by (from the copper belt of central Africa, where cobalt follows copper into the leach solution and is separated from it downstream) → 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
  • Cobalt → is extracted from (a cobalt ore, though most cobalt now arrives as a by-product of copper and nickel mining) → Cobaltite
  • Cobalt → is sourced from (much of world supply arrives as a by-product of copper mining rather than from cobalt-first operations) → Copper → is extracted from (the principal copper ore worldwide) → Chalcopyrite
  • Cobalt → is produced by (generally alongside copper or nickel rather than from a cobalt-first operation) → Smelting → takes as input (roasted to drive off sulfur, then reduced to copper) → Chalcopyrite

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

Downstream — what it becomes

  • Cobalt → is a source for (roughly seventy per cent of it mined in the Democratic Republic of the Congo and refined overwhelmingly in China, which is the concentration the whole low-cobalt programme is a response to) → NMC cathode → is used in (in long-range vehicles and anything that has to be carried, where the requirement is energy per kilogram and no phosphate cathode competes) → Lithium-ion cell → is used in (and portable computing came first by two decades) → Electronics manufacture → is associated with (and the supply chain it produced is the deepest and most concentrated in the world economy) → The semiconductor era complete chain
  • Cobalt → is a source for (and a phone battery is a meaningful cobalt consumer per unit of energy stored, which the tonnages hide because the cells are small) → Lithium cobalt oxide → is used in (in the smallest cells only — phones, laptops, cameras — where volume is the constraint and a few hundred cycles is a long enough life) → Lithium-ion cell → is used in (and portable computing came first by two decades) → Electronics manufacture → is associated with (and the supply chain it produced is the deepest and most concentrated in the world economy) → The semiconductor era complete chain
  • Cobalt → is a component of (a substantial addition, and one of the reasons aviation and battery demand compete for the same metal) → Nickel superalloy → is used in (cast as a single crystal, because at temperature and sustained load the failure mode is creep along grain boundaries — so the boundaries are removed entirely) → Turbine blade → is associated with (the jet engine created the superalloy industry, because no existing material survived the turbine inlet — and turbine temperature has risen about 500 °C since, almost entirely on the blade) → The wartime materials programmes complete chain
  • Cobalt → is used in (in the cathode of the older chemistries, and the component the industry has been designing away from) → Lithium-ion cell → is used in (and portable computing came first by two decades) → Electronics manufacture → is associated with (and the supply chain it produced is the deepest and most concentrated in the world economy) → The semiconductor era complete chain
  • Cobalt → is used in (the cathode, and the element carrying the supply problem no audit has closed) → Smartphone → is used in (and it is where four separate raw-material arguments meet — the 3TG conflict minerals, cobalt, the rare earths, and everything too dispersed to recover) → Electronics manufacture → is associated with (and the supply chain it produced is the deepest and most concentrated in the world economy) → The semiconductor era complete chain
  • Cobalt → is a component of (the balance, and both the reason it works hot and the reason it is expensive) → Samarium–cobalt magnet → is used as (weaker and untroubled by heat, which keeps it where temperature rather than strength is the constraint) → Permanent magnets

These are the most distinct paths onward. Cobalt ends up in others besides.