About minor metals
Editorial · sourcedWhat are minor metals?
"Minor metals" is a trade-association category, not a chemistry one. It is the membership scope of the Minor Metals Trade Association (MMTA), founded in London in 1973 to serve traders in low-volume non-ferrous metals that fall outside the LME contract set. The defining commercial property is small annual production (typically <100,000 t/year per metal), almost always as a by-product of another mineral's refining, and the absence of a regulated futures market — making professional brokerage and standardised specifications essential. The MMTA covers ~50 metals; the most actively traded include indium, gallium, germanium, tellurium, selenium, bismuth, cadmium, antimony, mercury, plus most rare earths and refractory metals.
How minor metals are priced
All minor metals are priced by benchmark assessment, not by exchange settlement. The two dominant pricing references for international trade are Fastmarkets (formerly Metal Bulletin, regulated benchmark administrator under UK BMR) and Argus Media. Both publish daily or weekly assessments in standardised form (e.g. "99.99% In ingot, in-warehouse Rotterdam, USD/kg"). For Chinese domestic spot prices the reference is Shanghai Metals Market (SMM). Many minor metals are also priced via MMTA member quote sheets and bilateral long-term contracts directly between producer and end-user.
Where minor metals come from
Almost every minor metal is a by-product:
- Bismuth, cadmium, indium — by-products of zinc refining (recovered from electrolytic Zn anode slimes and flue dusts).
- Tellurium, selenium — by-products of copper electrorefining (recovered from copper anode slimes).
- Gallium — by-product of alumina production from bauxite (Bayer process residual liquor).
- Germanium — by-product of zinc and coal-ash processing.
- Antimony — minor primary mining (China, Russia, Tajikistan) and by-product of lead refining.
- Mercury — historically primary cinnabar mining; now restricted under the Minamata Convention (in force 2017), output is largely a by-product of natural-gas processing and gold mining.
Who produces minor metals
Because output is a by-product, the producers are integrated zinc, copper and aluminium refiners rather than dedicated minor-metals miners. Key names: Korea Zinc (world's largest single producer of Pb, Zn, In, Ge), Umicore (precious-metals and minor-metals refining, Belgium), Boliden (Sweden, multi-metal smelting), Aurubis (Germany, copper-anode-slimes-based Se/Te), 5N Plus (Canada, semiconductor-grade refining), Indium Corporation (USA, In refining and electronic solders), Materion (Be and high-purity metals).
What minor metals are used for
Minor-metals demand is concentrated in electronics, semiconductors, solar PV and specialty alloys — applications where small volumes deliver disproportionate technological value:
- Bismuth — pharmaceuticals (Pepto-Bismol active ingredient), low-melting fusible alloys, lead-free solders.
- Cadmium — Ni-Cd batteries (declining), pigments, PV CdTe solar cells (First Solar).
- Indium — indium-tin-oxide (ITO) transparent conductive coatings for touchscreens and LCD displays — >70% of demand.
- Tellurium — CdTe solar PV (First Solar dominant consumer), thermoelectric coolers, alloying agent in steel and Cu.
- Selenium — glass decolourising agent, animal feed supplement, copper alloying agent (free-machining brass).
- Mercury — chlor-alkali production (legacy, being phased out under Minamata), artisanal gold mining (also being phased out), fluorescent lamps (legacy).
- Gallium — GaAs and GaN semiconductors (5G RF amplifiers, LEDs, satellite communications).
- Germanium — fibre-optic cable core, infrared optics, PET-plastic catalyst.
- Antimony — flame retardants (~50% of demand), lead-acid battery alloys, glass-clarifying agent.
Key facts about minor metals supply
- Most minor metals on this page are on the USGS 2025 Critical Minerals list (bismuth, indium, tellurium, gallium, germanium, antimony); cadmium and mercury are not.
- Because supply is by-product, minor-metals output is structurally insensitive to its own price — recovery is driven by the primary metal (Zn, Cu, Al). This makes minor-metals prices unusually volatile: a 50–100% annual move is common (e.g. gallium +400% during the 2023 China export-licence introduction).
- Mercury is unique among traded metals: the Minamata Convention (UN Environment, 2017) restricts primary mining and most international Hg trade; supply is now largely retrieval from natural-gas / oil-sands processing.