Selenium: Emissions
How copper refinery accounting sets selenium's footprint
How copper refinery accounting sets selenium's footprint What this tab covers The greenhouse-gas footprint of the commodity at a global level, split by lifecycle phase: extraction (or farming), refining and processing, movement, usage, and recycling or end of life. Intensities are per unit of product; the global total combines intensity with world output. Also covers other environmental impacts and the main levers to cut emissions. Emission intensity 15.6 t CO2e per t range 3.4-24.6 · cradle-to-gate, Aurubis RETORTE (Germany) selenium products, reference year 2025, with refining burdens allocated among silver, gold, PGM concentrate and crude selenium; 13.1 in 2024 and 24.6 in 2023. The German BAFA generic factor is 3.44 Global emissions per year 0.06 Mt CO2e per year 2025 · 15.6 t CO2e/t x 3,800 t (derived, indicative)Per t of selenium contained in products, cradle-to-gate. Intensity: Aurubis Environmental Fact Declaration Selenium 2025; BAFA Informationsblatt CO2-Faktoren v3.3 (2025) via Climatiq. Global total: Derived from Aurubis EFD 2025 and USGS MCS 2026.
Footprint by lifecycle phase
| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| Extraction | small allocated share of copper mining and smelting | – | copper ore mining, concentration and smelting | Included upstream in the Aurubis value but not split out | Aurubis EFD Selenium 2025 (qualitative) |
| Refining / processing | main share: anode-slime treatment, precious-metal refining, selenium distillation and conversion to compounds | – | electricity, roasting fuel, reagents | Year-to-year swings (24.6 to 13.1 to 15.6) reflect allocation among precious metals and plant energy mix | Aurubis EFD Selenium 2025 |
| Movement | negligible per tonne | – | drums by container | Not material | Qualitative |
| Usage | no direct emissions | – | glass, manganese electrolysis, feed, pigments | In electrolytic manganese, selenium dioxide raises current efficiency; sulfur dioxide can replace it but is less energy efficient | USGS MCS 2026 |
| Recycling / end of life | insignificant: EU end-of-life recycling input rate about 1% | – | electronics and photocopier scrap | Most uses (glass, feed, fertiliser, manganese) are dissipative, so selenium is lost to products and soils | USGS MCS 2026; EU CRM 2023 |
Other environmental impacts
Selenium is toxic in excess; it leaches from coal ash ponds and irrigation drainage. Coal combustion releases more selenium than is mined.
Levers to cut emissions
- Renewable power at slime-refining plants (the main driver of the Aurubis value)
- Raise recovery from copper slimes, adding supply without new mining
- Use spare capacity at existing plants rather than build new ones
- Keep selenium dioxide in manganese electrolysis where it saves electricity compared with sulfur dioxide
India
India refines about 90 t a year at Hindalco's Dahej copper complex, on a grid near 0.7 t CO2/MWh, and imports much more (13.8% of world import value in 2024). Its glass, pharma and feed users carry an embedded footprint of only about 15 kg CO2e per kg of selenium.
Emission figures are indicative global averages from the life-cycle studies named; actual footprints vary widely by site, energy mix and method.