Indium

A soft zinc by-product whose indium tin oxide coats flat-panel displays, now also drawn into 5G and AI data-centre optics.

Tech & minor metals · No. 40

• US critical 2025
• India critical 2023
• HHI 4,925 · highly concentrated

Every LCD and touchscreen needs indium tin oxide, yet indium comes mainly as a trace by-product of zinc smelting.

Chart: Illustration: Indium

Where it comes from

Chart: Map of where it comes from

Indium is recovered from sphalerite, the zinc sulphide mineral, at under 1 to 100 parts per million. Smelters gather it in dusts and residues and refine it to 99.99% metal.

Three things to know

1. Primary indium output grew 1,675% between 1975 and 2012, while zinc, its host, grew only 231%.
2. Refinery capacity of about 1,700 t sits well above 2025 output of 1,100 t, so the world has spare capacity.
3. The EU left indium off its 2023 critical list, with supply risk 0.6, though the US and India still list it.

The journey

1. 1 Zinc oreSphalerite with under 1 to 100 ppm
2. 2 SmeltingZinc concentrate processed for zinc first
3. 3 ResiduesIndium gathers in dusts and residues
4. 4 RefiningLeached and refined to 99.99%
5. 5 ProductsITO targets, solders, indium phosphide wafers

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