Element · Zn

Zinc

The metal that protects steel by corroding instead of it.

Zinc's dominant use is galvanising: coating steel so that the zinc, being more electrochemically active, corrodes in the steel's place. A scratch through a galvanised coating does not start rust at the scratch, because the surrounding zinc protects the exposed steel electrically. Paint cannot do this.

Alloyed with copper it makes brass, which has been in use for two thousand years and remains the standard material for anything that must be machined and not spark.

Uses

Zinc's largest use is galvanising — coating steel so that the zinc corrodes preferentially and the steel underneath does not. It is a sacrificial protection that works even where the coating is scratched, which is why it survives in real conditions rather than only in laboratories.

Zinc is also the other half of brass, a die-casting metal in its own right for small precise components, and, as zinc oxide, an ingredient in rubber compounding, sunscreen and skin ointments.

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 a source for

Indium — element · recovered almost entirely from zinc refining, so indium supply is set by zinc demand
Thallium — element · captured from the flue dusts of zinc smelting before it disperses
Silver — element · with lead, from the same polymetallic ores — sphalerite and galena carry silver together
Cadmium — element · cadmium substitutes for zinc in sphalerite and follows it through roasting; there is no cadmium ore and never has been
Germanium — element · from the flue dusts of zinc smelting, and from coal ash — dispersed at parts per million everywhere and concentrated nowhere

is used as

Corrosion protection — application · galvanising: zinc corrodes in the steel's place
Alloying — application · with copper, to make brass

is an alternative to

Bronze — alloy · brass and bronze are both copper alloys with quite different working properties
Cadmium — element · as a sacrificial plating on steel. Cadmium performs better in salt and is banned from most uses for being a cumulative poison, so zinc does the job almost everywhere now

is a component of

Brass — alloy · typically a fifth to a third; the proportion decides whether the alloy cold-works or casts

is produced by

Roasting — process · as the oxide, which is then reduced — roasting is the step that makes zinc sulfide smeltable
Solvent extraction and electrowinning — process · where an oxidised or low-grade ore does not justify a roaster, though most zinc still comes from the roasting route

is extracted from

Sphalerite — mineral · almost all zinc production Wikidata

is an input to

Alloying and melting — process · the addition that makes brass; it boils below copper's melting point, which is the difficulty

is found in

7000 series aluminium alloy — alloy · 4–8% · the principal alloying element, and what makes these the strongest aluminium alloys made
Zinc die-casting alloy — alloy · 94–96% · the balance, and it must be high-purity — lead and cadmium above a few hundredths of a per cent cause the casting to crumble over years
Ferrite — material · in both soft families, where it tunes the permeability and the frequency at which the material stops working
Sphalerite — mineral Wikidata

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 Zinc 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

Zinc → is produced by (as the oxide, which is then reduced — roasting is the step that makes zinc sulfide smeltable) → Roasting → takes as input (a copper sulfide; roasting drives off the sulfur that would otherwise prevent reduction) → Chalcopyrite
Zinc → is produced by (where an oxidised or low-grade ore does not justify a roaster, though most zinc still comes from the roasting route) → 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
Zinc → is extracted from (almost all zinc production) → Sphalerite
Zinc → is produced by (as the oxide, which is then reduced — roasting is the step that makes zinc sulfide smeltable) → Roasting → takes as input (roasted for its sulfur as much as for its iron) → Pyrite
Zinc → is produced by (as the oxide, which is then reduced — roasting is the step that makes zinc sulfide smeltable) → Roasting → takes as input (roasted to the oxide, the sulfur going to an acid plant rather than the air) → Galena
Zinc → is produced by (as the oxide, which is then reduced — roasting is the step that makes zinc sulfide smeltable) → Roasting → takes as input (roasted to zinc oxide before reduction or electrolytic winning) → Sphalerite

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

Downstream — what it becomes

Zinc → is a source for (with lead, from the same polymetallic ores — sphalerite and galena carry silver together) → Silver → is a component of (a few per cent in the lead-free alloys, which measurably raised world silver demand when the transition happened) → Solder → is used in (every joint on it, and tin-silver-copper since RoHS pushed the lead out from 2006) → Printed circuit board → is used in (and it is the change that made electronics manufacturable: assembly stopped being a wiring job and became a printing one) → 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
Zinc → is an input to (the addition that makes brass; it boils below copper's melting point, which is the difficulty) → Alloying and melting → produces (tin into copper — the first alloy anybody made deliberately) → Bronze → is used to make (cast in a two-piece mould with a core, which is what bronze does better than the copper it replaced) → Bronze socketed axe → is associated with → Bronze Age complete chain
Zinc → is a source for (from the flue dusts of zinc smelting, and from coal ash — dispersed at parts per million everywhere and concentrated nowhere) → Germanium → is used in (the first one, and displaced by silicon on the oxide rather than on any electrical property) → Transistor → is used in (the component every other modern technology is assembled from, and one nobody ever sees) → 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
Zinc → is a source for (recovered almost entirely from zinc refining, so indium supply is set by zinc demand) → Indium → is used as (as the transparent electrode in displays) → Lighting
Zinc → is a source for (captured from the flue dusts of zinc smelting before it disperses) → Thallium → is used as (thallium-201 as a cardiac imaging tracer) → Medical imaging
Zinc → is a component of (typically a fifth to a third; the proportion decides whether the alloy cold-works or casts) → Brass → is used as (in air rather than seawater — brass dezincifies in chloride) → Corrosion protection

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