Material Insights · Understanding the Material World

Cadmium and Zinc

Cadmium is recovered mainly as a by-product of zinc refining, so its primary supply follows zinc smelter output, not cadmium demand; toxicity rules restrict many of its uses, while CdTe thin-film solar panels are a growing outlet.

Cadmium (commodity) and Zinc (commodity): 4 relationships.

How they are linked

1. By-product of zinc refining

Joint production · Asymmetric · Zinc smelting → cadmium

Most zinc ores carry small amounts of cadmium, which is separated out during zinc refining.

  • about 23,000 t world refined cadmium output, 2025
  • $3.90/kg average free market cadmium price, 2025, down from $4.12 in 2024

Smelters remove cadmium whatever its price, so primary supply does not respond to cadmium demand, and the price eased from $4.12 to about $3.90 a kilogram between 2024 and 2025. Cadmium earns a small fraction of what zinc earns at the same smelter, so the dependence runs one way.

Sources: USGS

2. Same smelting countries

Geography and ownership · Strong · Zinc refining countries make cadmium

Cadmium is made where zinc is refined, so the leading zinc smelting countries are also the leading cadmium producers.

  • about 41% China's share of world refined cadmium, 2025 (9,500 of 23,000 t)
  • 4,300 t South Korea's refined cadmium output, 2025
  • 4.1 Mt China's zinc mine output, 2025

China leads both zinc mining and cadmium refining, and South Korea, with a large zinc smelting industry, is the second largest cadmium refiner. Any cut in zinc smelting, for example from low treatment charges, reduces cadmium supply too.

Sources: USGS; USGS

3. Toxicity rules

Policy · Medium · Rules restrict cadmium uses

Cadmium is toxic, so product rules cap its content, which pushes users towards substitutes while zinc smelters keep producing it.

  • 0.01% EU RoHS maximum cadmium concentration in electrical and electronic equipment, by weight in homogeneous materials
  • 0.002% (20 mg/kg) EU Batteries Regulation cadmium limit for portable batteries

Lithium-ion batteries can replace nickel-cadmium in many uses, and coatings such as zinc-nickel can replace cadmium plating except where surface properties are critical, such as aircraft fasteners. RoHS excludes photovoltaic panels in systems designed and installed by professionals for permanent use, which leaves room for CdTe solar. As uses shrink, zinc refiners still produce the cadmium, so it must be sold or stored safely.

Sources: USGS; EU, via legislation.gov.uk; EU, via legislation.gov.uk; SGS

4. CdTe thin-film solar

Transition · Rising · Solar demand → cadmium use

Cadmium telluride thin-film panels are a growing use, giving by-product cadmium an outlet in the energy transition.

  • about 14 GW a year expected US CdTe panel making capacity once a fifth plant ramps up in 2026

In the US, the leading CdTe panel maker began production at a fifth plant in mid-2025, expected to lift domestic capacity to about 14 GW a year in 2026. CdTe panels compete with crystalline silicon and can be recycled to recover cadmium. Growth here does not change cadmium supply, which still rests on zinc output.

Sources: USGS

For investors

Key learnings

  1. Cadmium supply follows zinc refining, so cadmium prices stay low when demand is weak and cannot call forth new supply when demand rises.
  2. Toxicity rules restrict battery, plating and pigment uses, while CdTe solar is the main growing outlet.
  3. Zinc smelter cuts in China or South Korea reduce cadmium supply directly.

What to track

  • Zinc smelter output and treatment charges: Lower smelter runs mean less cadmium (Monthly · International Lead and Zinc Study Group)
  • CdTe module shipments: The growing demand outlet for cadmium (Quarterly · company reports)
  • Cadmium free market price: Whether surplus is building or clearing (Monthly · Fastmarkets, USGS)

For policymakers

Key learnings

  1. Cadmium is unavoidable in zinc smelting, so pollution control and safe storage at zinc smelters matter more than supply security.
  2. India's zinc smelters, mainly Hindustan Zinc, recover cadmium, yet India recorded 6,374 t of cadmium imports in 2021-22, well above its 913 t a year of installed recovery capacity, so domestic by-product supply covers only part of use.
  3. Rules on cadmium in products should be set with the by-product flow in mind, so surplus cadmium has a safe destination.

What to track

  • Cadmium imports and exports: Whether domestic by-product supply meets use (Yearly · Indian Bureau of Mines, Ministry of Commerce)
  • Hazardous waste and effluent compliance at zinc smelters: Control of cadmium releases (Yearly · Central Pollution Control Board)

India

India recovers cadmium as a by-product of zinc smelting, mainly at Hindustan Zinc, with installed recovery capacity of 913 t a year and cadmium imports of 6,374 t in 2021-22 (Indian Bureau of Mines, 2022 yearbook); India mined about 870 kt of zinc in 2025.

Sources

  1. Mineral Commodity Summaries 2026: Cadmium, USGS (2026)
  2. Mineral Commodity Summaries 2026: Zinc, USGS (2026)
  3. Indian Minerals Yearbook 2022: Cadmium, Indian Bureau of Mines (2024)
  4. Directive 2011/65/EU (RoHS), as adopted, including Annex II, EU, via legislation.gov.uk (2011)
  5. Directive 2011/65/EU (RoHS), Article 2: Scope, EU, via legislation.gov.uk (2011)
  6. EU issues new regulation on batteries and waste batteries (Regulation (EU) 2023/1542), SGS (2023)