Wollastonite: Emissions
What we do and do not know about its 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.Per t of milled wollastonite, cradle-to-gate. Intensity: none found. Global total: USGS MCS 2026.
Footprint by lifecycle phase
| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| Extraction | a few kg CO2e/t of ore (analogue) | – | open-pit drilling, blasting and diesel haulage | comparable rock quarrying and crushing averages about 4.3 kg CO2/t (Mineral Products Association 2009 via BGS 2010), an indicative analogue | MPA 2009 via BGS 2010 |
| Refining / processing | not published | – | electricity for beneficiation, fine grinding and classification; surface treatment | fine and acicular grades need much more milling energy than ceramic powder; in China and India the grid is coal-heavy | USGS MCS 2026 |
| Movement | about 35 kg CO2e/t for 5,000 km by bulk ship (derived) | – | bagged product by road and container ship | large bulk ship about 0.007 kg CO2e per t-km, road truck 0.178 (ERM for The Crown Estate, 2010) | ERM for The Crown Estate, 2010 (derived) |
| Usage | avoided process CO2 up to about 0.38 t per t when it replaces calcite as the calcium source in ceramics | – | calcite (CaCO3) releases CO2 on firing; wollastonite does not | derived from stoichiometry: 0.483 t CaO per t of CaSiO3 would otherwise come from 0.86 t of CaCO3, releasing 0.38 t CO2 | stoichiometry (derived) |
| Recycling / end of life | not recycled | – | locked in tiles, plastics and brake pads | USGS reports no recycling. Crushed wollastonite can absorb CO2 by weathering to calcium carbonate (theoretical maximum about 0.38 t CO2 per t), which is being studied for carbon removal | USGS MCS 2026; stoichiometry (derived) |
Other environmental impacts
Respirable dust in milling. Skarn mining in Rajasthan disturbs small areas compared with bulk minerals.
Levers to cut emissions
- Replace calcite in tile bodies to cut firing CO2 (up to 0.38 t avoided per t of wollastonite, derived)
- Run fine-grinding mills on renewable power
- Use wollastonite as an asbestos substitute in friction products, removing a health hazard
- Explore enhanced weathering with fines and offcuts as a carbon sink
India
India is the second largest producer (120,000 t in 2025, USGS), almost all from Udaipur district, Rajasthan. Its milling runs on a grid of about 0.72 t CO2/MWh (CEA 2024, indicative), and the Morbi tile cluster is the main domestic user.
Emission figures are indicative global averages from the life-cycle studies named; actual footprints vary widely by site, energy mix and method.