Tellurium: Extraction
How copper refinery sludge became a solar ingredient
What this tab covers How it is mined, drilled or grown, and processed into a tradeable form: the main methods compared, their unit economics, by-products, and the companies that do this work globally and in India.Tellurium is one of the scarcer stable elements in the crust and is almost never mined for itself. USGS says more than 90% has come from anode slimes, the residue left when copper anodes are electrorefined. The rest comes from lead refinery skimmings and from smelter dusts and gases of bismuth, copper and lead-zinc ores. Slimes are treated to copper telluride, then refined. Supply therefore tracks electrolytic copper refining, not tellurium demand. Copper is the principal host for only two companions, selenium and tellurium (Nassar et al., pdf p. 3).
More than 90% of tellurium has come from anode slimes left by electrolytic copper refining (USGS 2026). The rest comes from lead refinery skimmings and from dusts and gases in bismuth, copper and lead-zinc smelting. So tellurium output follows copper refinery throughput, and only refineries that treat their slimes for tellurium contribute. China's tellurium output grew with a near-75% rise in its electrolytic copper capacity over ten years. A few primary telluride deposits, including one mined in China, are a minor source.
Methods compared
| Method | Share of supply | Typical scale | Recovery / efficiency | By-products | Unit cost |
|---|---|---|---|---|---|
| Recovery from copper refinery anode slimes | more than 90% of tellurium produced (USGS 2026) | Kennecott circuit 20 t/yr capacity for $2.9 million capex (Argus 2022); world refinery capacity 1,300 t (USGS 2026) | about 55% at current efficiency, up to 80% with enhanced recovery (NREL 2012); about 50-60% of Se and Te in ore is refined to metal (USGS Circular 1365) | gold, silver, selenium, platinum-group metals from the same slimes | n/a |
| Recovery from lead refinery skimmings and smelter dusts | under 10% (remainder after anode slimes, USGS 2026) | n/a | n/a | bismuth, antimony, lead | n/a |
| Primary telluride and gold-telluride ores | small | n/a | n/a | gold, bismuth | n/a |
How each method works
Recovery from copper refinery anode slimesAnode slimes are leached and roasted to recover precious metals and selenium. Tellurium is precipitated as copper telluride, then leached, purified and electrowon or reduced to metal. US refineries in Texas and Utah make copper telluride and export it for refining (USGS 2026).
Low capital cost on an existing refinery; supply is capped by copper refining and slime chemistry.
USGS MCS 2026; Argus (2022); NREL (2012); USGS Circular 1365 (2010) Recovery from lead refinery skimmings and smelter dustsTellurium concentrates in skimmings from lead bullion softening and in flue dusts and gases from bismuth, copper and lead-zinc smelting. These are treated alongside other minor metals.
Uses existing waste streams; small and irregular volumes.
USGS MCS 2026 Primary telluride and gold-telluride oresChina operates a primary tellurium mine, and companies explore gold-telluride and bismuth-telluride deposits worldwide (USGS via Earth magazine 2018). Sweden reports tellurium in concentrate, 48 t in 2025 (USGS).
Could add supply independent of copper; few deposits are rich enough.
Earth magazine / USGS (George 2018); USGS MCS 2026 Unit economics are indicative ranges from the sources named; costs vary widely by deposit, region and year.By-product supply
Companionality is about 95%: tellurium comes almost entirely from copper anode slimes. It is worth a tiny fraction of the copper, so copper output never responds to tellurium prices. Recovery rates are low (about 55%), and an estimated 1,200 t a year could be recovered from slimes against actual output near 500 t in 2008 (USGS Circular 1365). Supply growth therefore comes from new slime circuits, as at Kennecott in 2022, not from mining.
Share produced as a by-product
About 95% of primary supply comes as a by-product of copper (Nassar, Graedel & Harper 2015, approximate).Who does it: global
| Company | Country | Activity | Volume | Year | Source |
|---|---|---|---|---|---|
| 5N Plus not published | Canada | refining tellurium to metal and CdTe; main supplier to First Solar; St George, Utah plant | not published | 2025 | Argus (2022) |
| Rio Tinto (Kennecott, Utah) | US | tellurium recovery from copper refinery slimes | 20 t/yr capacity | 2022 start | Argus (2022) |
| First Solar tellurium volume not published | US | CdTe module maker, the largest tellurium consumer | 14 GW/yr expected US module capacity at full ramp-up | 2026-2027 | USGS MCS 2026 |
| Chinese copper refiners (country total) operator volumes not published | China | tellurium from anode slimes and a primary mine | 800 t Te (country refinery output) | 2025 | USGS MCS 2026 |
| Boliden (Ronnskar smelter) Sweden's figure is a reported country total; Boliden is the Swedish copper smelter | Sweden | tellurium in concentrate from copper smelting | 48 t Te (Sweden reported output, concentrate) | 2025 | USGS MCS 2026 |
| Russian copper refiners (country total) operator volumes not published | Russia | tellurium from anode slimes | 67 t Te (country refinery output) | 2025 | USGS MCS 2026 |
Who does it: India
| Company | Country | Activity | Volume | Year | Source |
|---|---|---|---|---|---|
| Hindustan Copper (Ghatsila, Jharkhand) no tellurium output since 2004-05 | India | tellurium recovery plant at the Ghatsila smelter | 0 t Te | 2019-20 | IBM Indian Minerals Yearbook 2020 (Selenium and Tellurium) |
| Hindalco Industries (Birla Copper, Dahej) not published | India | copper smelting and refining with precious-metal recovery from anode slimes | not published | 2025 | IBM Indian Minerals Yearbook 2020; USGS MCS 2026 lists India among possible refined-tellurium producers |
India's copper smelters (Hindalco at Dahej, Hindustan Copper at Ghatsila) generate tellurium-bearing slimes, but no refined tellurium output is published; USGS lists India only as a possible producer. India imported about 3 t in 2019-20, mainly from China (IBM 2020).