How iridium is made
For every 190 tonnes of platinum, refiners isolate only 7.5 tonnes of this metal, which even aqua regia cannot touch.
- stations
- 6
- things upstream
- 14
- raw sources
- 8
- steps from the ground
- 4
The short version
Nobody mines for it alone. It rides along in platinum ores and in copper and nickel deposits, and it is what remains after nearly everything else has dissolved. Refiners collect the sludge from electrorefining cells, dissolve away the platinum and palladium, then force the stubborn residue into solution and drop it out as a salt that is reduced to powder.
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Smelt the host ores
Platinum ore from South Africa's Bushveld, and copper and nickel ores from places such as Sudbury and Norilsk, are mined and smelted for their main metals. A trace of this metal comes along, with crustal rock averaging just 0.001 ppm.
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Collect the anode mud
During electrorefining of copper and nickel, noble metals do not dissolve. They settle to the bottom of the cell as anode mud, along with silver, gold, selenium and tellurium. This sludge is the starting point.
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Dissolve away the platinum
Acid treatment takes platinum and palladium into solution. This metal stays behind in the acid-insoluble residue, which is how it was found in 1803.
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Force the residue open
Refiners make the stubborn solids soluble by fusing them with sodium peroxide and extracting with acid, or by treating them with chlorine in hydrochloric acid.
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Drop out the salt
From solution, an ammonium salt with an intense dark color is precipitated, or organic amines pull the metal out. This compound is the main intermediate in purification.
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Reduce and sinter powder
The purified compound is reduced to a metal powder. Solid pieces are so hard and brittle that they are hard to machine or form, so powder metallurgy shapes most of the parts, such as spark plug tips and crucibles.
Goes in
Worth repeating
- Only about 6,800 kilograms of iridium were produced in 2023.
- A layer of unusually iridium-rich clay at the Cretaceous-Paleogene boundary pointed to the impact behind the extinction of the non-avian dinosaurs.
- The international prototype kilogram is an alloy of 90 percent platinum and 10 percent iridium.
Back to the ground
Follow every input upstream and iridium starts as these 8 raw sources.
Everything it is made of See it on the map
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Sources
Cite this page: "How iridium is made." Assembly Line, 2026-11-03. https://assemblyline.org/make/iridium