# Our motor buyer wants the carbon footprint of the rare earth magnets we buy from Baotou. What do we ask?

Canonical: https://senseible.earth/answers/baotou-rare-earth-magnet-supplier-carbon-data

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.

- [Primary data share meaning](https://senseible.earth/answers/primary-data-share-meaning)
- [Data quality rating explained](https://senseible.earth/answers/data-quality-rating-dqr-explained)
- [Battery pack carbon per kWh](https://senseible.earth/answers/battery-pack-assembly-carbon-footprint-per-kwh)

Sources: [GHG Protocol Corporate Value Chain (Scope 3) Standard](https://ghgprotocol.org/corporate-value-chain-scope-3-standard), [GHG Protocol standards, including the Product Standard](https://ghgprotocol.org/standards), [ISO 14064 and ISO 14067 standards](https://www.iso.org)

Last reviewed 2026-10-22.