# Scandium: Emissions

Why each tonne of oxide carries thousands of tonnes of CO2

Source page: https://www.materialinsights.org/commodities/scandium/emissions/

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 3,940 t CO2e per t range 743-5,500 across published routes · cradle-to-gate, Sc2O3 from rare-earth tailings, mass allocation (Wang et al. 2020). Other studies: titanium dioxide acid waste 743 (Zhang et al. 2018); bauxite residue 5,290 with economic allocation or 1,930 with mass allocation (Hengevoss et al. 2024); about 5,500 (Koltun & Tharumarajah 2014) Global emissions per year 0.30 Mt CO2e per year 2025 · 3,940 t CO2e/t x 80 t of oxide (derived); range about 0.06-0.44 Mt using the published spread

Per t of scandium oxide (Sc2O3), cradle-to-gate. Intensity: Hengevoss et al. 2024, Cleaner Waste Systems 7:100129, which reviews the other studies. Global total: Derived from Hengevoss et al. 2024 and USGS MCS 2026.

#### Share of footprint by lifecycle phase
 Refining / processing 96%

#### Footprint by lifecycle phase

| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| **Extraction** | low or zero for waste feedstocks | – | residues and tailings enter the system burden-free in most studies | Primary laterite projects in Australia would carry mining burdens | Hengevoss et al. 2024 |
| **Refining / processing** | about 96% of footprint for Al-Sc2% alloy: acid leaching 63% (energy 38%, sulfuric acid 25%), ion recovery and neutralisation 27%, other steps under 5% each | 96% | electricity, sulfuric acid, CO2 released when neutralising acid with limestone | About 1,800 kg of residue is processed per kg of alloy, with about 25% overall yield | Hengevoss et al. 2024 (Al-Sc2% alloy shares) |
| **Movement** | negligible per tonne | – | air or courier shipment of kilogram lots | Not material | Qualitative |
| **Usage** | no direct emissions | – | aerospace alloys, solid oxide fuel cells | Enabling: lighter airframes and efficient fuel cells; reduction to alloy with primary aluminium adds about 4% | Hengevoss et al. 2024; USGS MCS 2026 |
| **Recycling / end of life** | none: no recycling reported; EU end-of-life recycling input rate 0% | – | scandium is diluted in aluminium scrap | Al-Sc scrap is remelted as aluminium, so the scandium is lost | USGS MCS 2026; EU CRM 2023 |

#### Other environmental impacts

Large volumes of acid and neutralisation residue per kilogram. Using bauxite residue or titanium wastes as feed can reduce legacy waste stockpiles.

#### Levers to cut emissions

- Low-carbon electricity at leaching plants (energy is about 38% of the alloy footprint)
- Higher overall yield than the current about 25%
- Recover and reuse acid, and neutralise with low-CO2 alkalis instead of limestone
- Co-recover scandium from existing titanium and nickel HPAL streams rather than new mining

#### India

India has no scandium production. Its bauxite residue (red mud) from alumina refineries in Odisha and elsewhere is a possible future feedstock, but any plant on India's coal-heavy grid would sit at the high end of the 743-5,500 t CO2e/t range unless supplied with clean power.
 Emission figures are indicative global averages from the life-cycle studies named; actual footprints vary widely by site, energy mix and method.

## Other sections

- [Summary](https://www.materialinsights.org/commodities/scandium/index.md)
- [Overview](https://www.materialinsights.org/commodities/scandium/overview/index.md)
- [Correlation](https://www.materialinsights.org/commodities/scandium/correlation/index.md)
- [Extraction](https://www.materialinsights.org/commodities/scandium/extraction/index.md)
- [Production](https://www.materialinsights.org/commodities/scandium/production/index.md)
- [Stocks](https://www.materialinsights.org/commodities/scandium/stocks/index.md)
- [Cycles](https://www.materialinsights.org/commodities/scandium/cycles/index.md)
- [Trading](https://www.materialinsights.org/commodities/scandium/trading/index.md)
- [Movement](https://www.materialinsights.org/commodities/scandium/movement/index.md)
- [Criticality](https://www.materialinsights.org/commodities/scandium/criticality/index.md)
- [Characteristics](https://www.materialinsights.org/commodities/scandium/characteristics/index.md)
- [Relationships](https://www.materialinsights.org/commodities/scandium/links/index.md)