Iodine: Emissions
How desert leaching sets iodine's carbon footprint
How desert leaching sets iodine's carbon 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 14.8 t CO2e per t range about 9-15 (lower with renewable power) · cradle-to-gate, caliche route, economic allocation 73% iodine / 27% sodium nitrate Global emissions per year 0.50 Mt CO2e per year 2025 · 14.8 t CO2e/t x about 34,000 t (excluding US); applies the caliche intensity to all routes, so indicativePer 1 t of iodine prill (at least 99.8%), cradle-to-gate, Chilean caliche route. Intensity: Roche, Muhl and Finkbeiner 2023, Int J Life Cycle Assess 28:1132-1141. Global total: Derived from Roche et al. 2023 and USGS MCS 2026.
Share of footprint by lifecycle phase
Extraction 45% Refining / processing 50% Movement 5%Footprint by lifecycle phase
| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| Extraction | about 6-7 t CO2e/t (indicative) | 45% | diesel for blasting, loading and hauling caliche; heap-leach pumping | Mining is the largest single GWP contributor; about 63 GJ of diesel per t of iodine for mining and transport | Roche et al. 2023 (split indicative) |
| Refining / processing | about 7 t CO2e/t (indicative) | 50% | grid electricity (about 38 GJ per t), hydrogen peroxide, sulphur and sulphur dioxide, kerosene, sodium hydroxide | Iodide production dominates acidification; at the final iodine step electricity gives about 44% and hydrogen peroxide about 39% of GWP | Roche et al. 2023 |
| Movement | small, under 1 t CO2e/t (indicative) | 5% | trucking within Chile; container shipping to Asia and Europe | High value per tonne means freight emissions are minor | Roche et al. 2023; IMO Fourth GHG Study 2020 (indicative) |
| Usage | not applicable | – | iodine is consumed in drugs, contrast media, film and feed | No direct use-phase emissions. Small enabling role: CF3I (trifluoroiodomethane) is a low-GWP refrigerant and fire-suppressant ingredient | USGS MCS 2026 (uses) |
| Recycling / end of life | not published | – | recovery from spent contrast media, LCD film manufacture and process streams | About 5,000 t a year of secondary iodine (2012), mostly in Japan; avoids the energy-intensive primary route | Roskill 2013 |
Other environmental impacts
Blue water use of about 130 m3 per t of iodine, mostly in heap leaching in the Atacama desert. Sulphur dioxide drives about 89% of acidification. Large waste heaps of leached caliche.
Levers to cut emissions
- Renewable electricity cuts GWP by about 33-39% (Roche et al. 2023)
- Switching to natural gas cuts GWP only about 17% (Roche et al. 2023)
- Electric or trolley-assisted haulage to cut the diesel share in mining
- Seawater or recycled water in heap leaching to ease Atacama water stress
- SQM targets carbon-neutral iodine by 2030 (SQM Sustainability Report 2021)
India
India produces no iodine and imported 13.1% of world import value in 2024, so its footprint is imported embodied emissions of about 14.8 t CO2e per t from Chilean caliche (Roche et al. 2023; UN Comtrade 2024).
Emission figures are indicative global averages from the life-cycle studies named; actual footprints vary widely by site, energy mix and method.