Our motor buyer wants the carbon footprint of the rare earth magnets we buy from Baotou. What do we ask?
Ask the magnet maker for a cradle to gate footprint per kilogram covering separation, metal making, alloy casting and sintering, with the electricity source. Magnets are not CBAM goods, so this is a footprint request; if no figure comes, label any estimate clearly.
Where the emissions are
- Rare earth separation, which uses chemicals and heat.
- Metal production by electrolysis, which uses a lot of electricity.
- Alloy casting, milling, sintering and heat treatment of the magnets.
What to ask the supplier
- Footprint per kilogram of magnet, with the system boundary stated.
- Electricity used per kilogram and where it came from.
- Which stages it runs itself and which it buys in.
If the supplier has no figure
Use a published estimate for the material and mark it as secondary data. Keep asking: magnets can be a large share of a motor's footprint, and buyers increasingly expect primary data.
What Senseible does here
Senseible reads supplier invoices into dated, fingerprinted records, so each purchased material in a Scope 3 figure traces back to its document.
Sources: GHG Protocol Corporate Value Chain (Scope 3) Standard, GHG Protocol standards, including the Product Standard, ISO 14064 and ISO 14067 standards
Last reviewed 2026-10-22.