Element · Zr

Zirconium

A metal chosen for nuclear fuel cladding because it lets neutrons through.

Zirconium's defining property for its main industrial use is negative: it barely absorbs neutrons. That, plus good corrosion resistance in hot water, makes zirconium alloys the standard cladding for nuclear fuel rods, where a neutron-absorbing material would poison the reaction.

Its oxide, zirconia, is a tough ceramic used in dental crowns and thermal barrier coatings, and cubic zirconia — the synthetic gemstone — is the same compound stabilised into a cubic structure.

Uses

Zirconium's defining use is nuclear. It is nearly transparent to neutrons and resists corrosion in hot water, which makes zirconium alloy the cladding around reactor fuel — a role with almost no alternative. Its one serious flaw is that at very high temperature it reacts with steam and releases hydrogen, which is what exploded at Fukushima.

Zirconia ceramic is hard, tough and biologically inert, so it appears in dental crowns, hip joints and cutting tools. Zircon sand is a foundry mould material and an opacifier in 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 used as

Nuclear fuel — application · fuel cladding, chosen because it lets neutrons through

is extracted from

Zircon — mineral · the only significant source, and of hafnium with it Wikidata

is produced by

Kroll process — process · reduced from the tetrachloride with magnesium, by the same route and in the same kind of vessel as titanium

is an alternative to

Titanium — element · in corrosion service. Zirconium resists hot acids titanium does not, titanium resists seawater and chloride better, and the two split the chemical plant market on which fluid is in the pipe

is used in

Energy generation — industry · nuclear fuel cladding, used because it is nearly transparent to neutrons — a property no other structural metal has

is found in

Zirconia — compound · and the crystal structure it takes is the entire subject of the material
Zircon — 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 Zirconium 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

Zirconium → is produced by (reduced from the tetrachloride with magnesium, by the same route and in the same kind of vessel as titanium) → 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 the brine the cell electrolyses, and as the source of the hydrogen that comes off the cathode) → Water → is sourced from (by desalination, where energy is cheap and coastline available — the only route that adds fresh water rather than moving it) → Seawater
Zirconium → is extracted from (the only significant source, and of hafnium with it) → Zircon
Zirconium → is produced by (reduced from the tetrachloride with magnesium, by the same route and in the same kind of vessel as titanium) → 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
Zirconium → is produced by (reduced from the tetrachloride with magnesium, by the same route and in the same kind of vessel as titanium) → 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
Zirconium → is produced by (reduced from the tetrachloride with magnesium, by the same route and in the same kind of vessel as titanium) → Kroll process → takes as input (converts the ore to a distillable tetrachloride, which is how the purification is done) → Chlorine → is extracted from (by electrolysis of brine, which yields chlorine and sodium hydroxide together) → Halite
Zirconium → is produced by (reduced from the tetrachloride with magnesium, by the same route and in the same kind of vessel as titanium) → 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 (the largest single use of salt, and the process the whole chlorine and caustic soda industry rests on) → Salt → is produced by (in the solar route — the same process, read from the other end) → Brine evaporation

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

Downstream — what it becomes

Zirconium → is used as (fuel cladding, chosen because it lets neutrons through) → Nuclear fuel
Zirconium → is used in (nuclear fuel cladding, used because it is nearly transparent to neutrons — a property no other structural metal has) → Energy generation