Material Insights · Understanding the Material World

Copper and Tellurium

More than 90% of tellurium has come from copper anode slimes, and about 70% of it now goes into cadmium telluride solar panels, so solar growth leans on a by-product of copper refining.

Copper (commodity) and Tellurium (commodity): 3 relationships.

How they are linked

1. Recovered from anode slimes

Joint production · Asymmetric · Copper refining yields tellurium

Tellurium in copper concentrate collects in the slimes left by electrorefining, from which refiners recover it with selenium and precious metals; the rest comes mainly from lead refining and smelter dusts.

  • more than 90% of tellurium produced from copper anode slimes
  • 70% of 2025 world tellurium use in solar cells

Supply follows copper cathode output: US recovery fell in 2025 because US refineries made less cathode. Demand is driven by cadmium telluride thin-film panels, so a solar build-out cannot pull more tellurium from copper refineries in the short run, and prices rise instead. Copper produced by leaching and electrowinning leaves no anode slimes and so yields no tellurium.

Sources: US Geological Survey

2. Solar maker sources copper by-product

Physical flow · Medium · First Solar secures tellurium refined from Kennecott copper by-product

First Solar, which uses cadmium telluride in its thin-film panels, partners with the refiner 5N Plus to refine the tellurium by-product of Rio Tinto's Kennecott copper operation in Utah, tying part of its feedstock to one copper operation.

5N Plus also holds a minimum-volume contract with First Solar, whose volume was earlier raised by 50% for two years (reported in February 2025). The arrangement shows how a solar supply chain can depend on the operating rate of a single copper refinery.

Sources: Argus Media

3. China dominates refining

Shared risk · Strong · Tellurium supply concentrated where copper is refined

China refines the most copper, about 45% of world refined output in 2024, and is also the leading refined tellurium producer; it has also tightened tellurium export rules.

  • about 80% China's share of estimated 2025 world tellurium output
  • $150 per kg European tellurium price, 2025 average, up 84%

From February 2025 China required exporters to document end users and end uses, with a new licence for any change of recipient or use. Prices rose sharply in 2025: about 84% in Europe and about 60% in the US, to about $120 per kg.

Sources: US Geological Survey; US Geological Survey

For investors

Key learnings

  1. Tellurium supply is capped by copper electrorefining, so CdTe solar growth shows up mainly as higher tellurium prices.
  2. CdTe makers outside China secure supply from a few copper refineries, as First Solar does through 5N Plus and Kennecott.
  3. European tellurium prices rose about 84% in 2025, the year China's export documentation rules took effect, a cost risk for thin-film module makers.

What to track

  • Tellurium price, Europe and US: Signals by-product supply strain and CdTe module cost pressure (Monthly · Fastmarkets, Argus)
  • CdTe module production capacity: Main driver of tellurium demand (Quarterly · First Solar reports)
  • Refined copper output outside China: Sets non-Chinese tellurium supply (Monthly · ICSG)

For policymakers

Key learnings

  1. India's CdTe module plant creates domestic tellurium demand, while India's own copper refineries are a possible by-product source.
  2. Tellurium supply security rests on recovery at copper refineries; it cannot readily be raised by opening mines.
  3. China's export documentation rules show that by-product metals can be used as trade levers just like mined ones.

What to track

  • India tellurium and CdTe imports: Show dependence of domestic thin-film production on imports (Monthly · DGCI&S)
  • China tellurium export rules: Changes affect supply to Indian and other non-Chinese users (As announced · China Ministry of Commerce)

India

First Solar inaugurated a 3.3 GW cadmium telluride module plant in India in 2024, so part of India's module output now depends on tellurium; India refined 545 kt of copper in 2024, whose anode slimes are a potential domestic source.

Sources

  1. Mineral Commodity Summaries 2026: Tellurium, US Geological Survey (2026)
  2. Mineral Commodity Summaries 2026: Copper, US Geological Survey (2026)
  3. 5N Plus expects extra Te spot business from First Solar, Argus Media (2025)
  4. Juniper, First Solar sign 1GW module supply deal for Indian solar PV, PV Tech (2024)