---
title: "How an actuator magnet is made"
description: "A zoomable process map of the sintered NdFeB magnet in an actuator, from rare earth ore to a magnetised rotor segment: every step with cited temperatures, particle sizes and yields, who runs it and which country holds it."
canonical: https://actuatorlist.com/manufacturing
last-updated: 2026-11-03T08:48:14.000Z
---
# How an actuator magnet is made

The permanent magnet at the heart of an actuator, step by step: 20 steps in four stages (mining, separation, metal and alloy, magnet), with the heavy rare earth branch, grain boundary diffusion and the scrap loop. As of November 2026. Interactive map: https://actuatorlist.com/manufacturing (deep link a step with `#step=<id>`). JSON: https://actuatorlist.com/api/v1/processes/magnet.

Numbers are each source's published figure for one plant, paper or patent; a range is the spread that source gives, not a world average. Country concentration is the stage's share of world output from [/metals](https://actuatorlist.com/metals.md).

## How an NdFeB magnet is made (`magnet`)

20 steps. Map: https://actuatorlist.com/manufacturing. JSON: https://actuatorlist.com/api/v1/processes/magnet.

### Mining

Stage concentration: concentrated: 🇨🇳 China ~69%[^2] (2025).

#### 1. Open-pit mining (`open-pit-mining`)

Blast and haul bastnaesite or monazite ore from terraced pits.[^1][^2]

- In: Hard-rock ore body. Out: Run-of-mine ore.
- Key numbers: Ore grade 7.06 % REO[^1]; World output ~390 kt[^2] (estimate, 2025).
- Who does it: MP Materials.
- Country concentration: concentrated: 🇨🇳 China ~69%[^2] (2025).
- Feeds: `beneficiation`.
- Elements: [Nd](https://actuatorlist.com/metals?element=nd), [Pr](https://actuatorlist.com/metals?element=pr).
- Map: https://actuatorlist.com/manufacturing#step=open-pit-mining

#### 2. Ionic clay leaching (`ionic-clay-leaching`)

Salt solution washes heavy rare earths off weathered clay.[^3][^4]

- In: Ion-adsorption clay, Ammonium sulfate. Out: Rare earth leach liquor.
- Key numbers: Clay grade 0.05-0.3 wt%[^3].
- Who does it: China Rare Earth Group.
- Country concentration: no public country split.
- Feeds: `solvent-extraction`.
- Elements: [Dy](https://actuatorlist.com/metals?element=dy), [Tb](https://actuatorlist.com/metals?element=tb).
- Map: https://actuatorlist.com/manufacturing#step=ionic-clay-leaching

#### 3. Flotation (`beneficiation`)

Crushed ore froths; rare earth minerals float off as concentrate.[^5]

- In: Run-of-mine ore. Out: Mineral concentrate.
- Key numbers: Concentrate 60 % REO[^5]; Recovery 65-70 %[^5].
- Who does it: MP Materials.
- Country concentration: concentrated: 🇨🇳 China ~69%[^2] (2025).
- Feeds: `cracking`.
- Elements: [Nd](https://actuatorlist.com/metals?element=nd), [Pr](https://actuatorlist.com/metals?element=pr).
- Map: https://actuatorlist.com/manufacturing#step=beneficiation

### Separation

Stage concentration: monopolized: 🇨🇳 China ~91%[^7] (2024).

#### 4. Acid cracking (`cracking`)

Roast concentrate in sulfuric acid, then leach rare earths into water.[^6]

- In: Mineral concentrate, Sulfuric acid. Out: Mixed rare earth solution.
- Key numbers: Acid-roasted 90 %[^6].
- Who does it: China Northern Rare Earth, MP Materials.
- Country concentration: monopolized: 🇨🇳 China ~91%[^7] (2024).
- Feeds: `solvent-extraction`.
- Elements: [Nd](https://actuatorlist.com/metals?element=nd), [Pr](https://actuatorlist.com/metals?element=pr).
- Map: https://actuatorlist.com/manufacturing#step=cracking

#### 5. Solvent extraction (`solvent-extraction`)

Mixer-settler cascades pull neighbouring rare earths apart, stage by stage.[^8]

- In: Mixed rare earth solution, P507 extractant. Out: NdPr solution, Heavy rare earth fraction.
- Key numbers: Pr/Nd stages 62 stages[^8] (model, 2026); Pr/Nd factor 1.7[^8].
- Who does it: China Northern Rare Earth, Shenghe Resources, MP Materials, China Rare Earth Group.
- Country concentration: monopolized: 🇨🇳 China ~91%[^7] (2024).
- Feeds: `precipitation`, `heavy-separation`.
- Elements: [Nd](https://actuatorlist.com/metals?element=nd), [Pr](https://actuatorlist.com/metals?element=pr).
- Map: https://actuatorlist.com/manufacturing#step=solvent-extraction

#### 6. Heavy REE separation (`heavy-separation`)

Separate cascades isolate dysprosium and terbium from the heavy fraction.[^9]

- In: Heavy rare earth fraction. Out: Dy oxide, Tb oxide.
- Key numbers: Tb circuit 37 stages[^9]; Dy circuit 39 stages[^9].
- Who does it: China Rare Earth Group.
- Country concentration: monopolized: 🇨🇳 China ~95%[^10] (2025).
- Feeds: `calciothermic-reduction`.
- Elements: [Dy](https://actuatorlist.com/metals?element=dy), [Tb](https://actuatorlist.com/metals?element=tb).
- Map: https://actuatorlist.com/manufacturing#step=heavy-separation

#### 7. Precipitate and calcine (`precipitation`)

Oxalic acid drops rare earth oxalate; a kiln bakes it to oxide.[^11]

- In: NdPr solution, Oxalic acid. Out: NdPr oxide.
- Key numbers: Calcining 900 °C[^11]; Kiln time 2 h[^11].
- Who does it: China Northern Rare Earth, MP Materials.
- Country concentration: monopolized: 🇨🇳 China ~91%[^7] (2024).
- Feeds: `electrolysis`.
- Elements: [Nd](https://actuatorlist.com/metals?element=nd), [Pr](https://actuatorlist.com/metals?element=pr).
- Map: https://actuatorlist.com/manufacturing#step=precipitation

### Metal & alloy

Stage concentration: monopolized: 🇨🇳 China ~90%[^14] (2023).

#### 8. Molten-salt electrolysis (`electrolysis`)

Current through a fluoride bath reduces oxide to liquid NdPr metal.[^12][^13]

- In: NdPr oxide, Fluoride salt bath. Out: NdPr metal.
- Key numbers: Bath 1050 °C[^12]; Energy ~8 kWh/kg[^12] (estimate, 2025); Current eff. 65-78 %[^13].
- Who does it: China Northern Rare Earth, Shenghe Resources, MP Materials.
- Country concentration: monopolized: 🇨🇳 China ~90%[^14] (2023).
- Feeds: `strip-casting`.
- Elements: [Nd](https://actuatorlist.com/metals?element=nd), [Pr](https://actuatorlist.com/metals?element=pr).
- Map: https://actuatorlist.com/manufacturing#step=electrolysis

#### 9. Dy/Tb metal reduction (`calciothermic-reduction`)

Calcium strips fluorine from Dy or Tb fluoride, leaving metal.[^15]

- In: Dy oxide, Tb oxide, Calcium. Out: Dy metal, Tb metal.
- Key numbers: Reduction 1450-1460 °C[^15]; Yield 85.7 %[^15].
- Who does it: China Rare Earth Group.
- Country concentration: monopolized: 🇨🇳 China ~90%[^14] (2023).
- Feeds: `strip-casting`, `grain-boundary-diffusion`.
- Elements: [Dy](https://actuatorlist.com/metals?element=dy), [Tb](https://actuatorlist.com/metals?element=tb).
- Map: https://actuatorlist.com/manufacturing#step=calciothermic-reduction

#### 10. Strip casting (`strip-casting`)

Molten alloy hits a chilled copper wheel and freezes into flakes.[^16][^17]

- In: NdPr metal, Iron, Ferroboron. Out: NdFeB alloy flakes.
- Key numbers: Cooling rate ~10000 K/s[^16] (estimate, 2015); Flake 0.3 mm[^17].
- Who does it: JL MAG Rare-Earth, Shin-Etsu Chemical.
- Country concentration: monopolized: 🇨🇳 China ~90%[^14] (2023).
- Feeds: `hydrogen-decrepitation`.
- Elements: [Nd](https://actuatorlist.com/metals?element=nd), [Pr](https://actuatorlist.com/metals?element=pr).
- Map: https://actuatorlist.com/manufacturing#step=strip-casting

### Magnet

Stage concentration: monopolized: 🇨🇳 China ~94%[^7] (2024).

#### 11. Hydrogen decrepitation (`hydrogen-decrepitation`)

Absorbed hydrogen swells grain boundaries and shatters flakes to coarse powder.[^18]

- In: NdFeB alloy flakes, Hydrogen. Out: Coarse powder.
- Key numbers: H2 pressure 0.1-0.25 MPa[^18]; Degassing 300-400 °C[^18].
- Who does it: JL MAG Rare-Earth, Shin-Etsu Chemical.
- Country concentration: monopolized: 🇨🇳 China ~94%[^7] (2024).
- Feeds: `jet-milling`.
- Elements: [Nd](https://actuatorlist.com/metals?element=nd), [Pr](https://actuatorlist.com/metals?element=pr).
- Map: https://actuatorlist.com/manufacturing#step=hydrogen-decrepitation

#### 12. Jet milling (`jet-milling`)

Nitrogen jets smash particles together down to single-grain size.[^19]

- In: Coarse powder, Nitrogen. Out: Fine powder.
- Key numbers: Particle size 2-5 µm[^19].
- Who does it: JL MAG Rare-Earth, Shin-Etsu Chemical.
- Country concentration: monopolized: 🇨🇳 China ~94%[^7] (2024).
- Feeds: `field-pressing`.
- Elements: [Nd](https://actuatorlist.com/metals?element=nd), [Pr](https://actuatorlist.com/metals?element=pr).
- Map: https://actuatorlist.com/manufacturing#step=jet-milling

#### 13. Pressing in field (`field-pressing`)

A magnetic field aligns the powder while punches press it.[^20][^19]

- In: Fine powder. Out: Green compact.
- Key numbers: Green density 50-70 %[^20].
- Who does it: JL MAG Rare-Earth, Shin-Etsu Chemical.
- Country concentration: monopolized: 🇨🇳 China ~94%[^7] (2024).
- Feeds: `sintering`.
- Elements: [Nd](https://actuatorlist.com/metals?element=nd), [Pr](https://actuatorlist.com/metals?element=pr).
- Map: https://actuatorlist.com/manufacturing#step=field-pressing

#### 14. Sintering and annealing (`sintering`)

Vacuum furnace fuses the compact to full density, then anneals it.[^19]

- In: Green compact. Out: Sintered block.
- Key numbers: Sintering 1000-1100 °C[^19]; Anneal 400-600 °C[^19].
- Who does it: JL MAG Rare-Earth, Shin-Etsu Chemical.
- Country concentration: monopolized: 🇨🇳 China ~94%[^7] (2024).
- Feeds: `machining`, `grain-boundary-diffusion`.
- Elements: [Nd](https://actuatorlist.com/metals?element=nd), [Pr](https://actuatorlist.com/metals?element=pr).
- Map: https://actuatorlist.com/manufacturing#step=sintering

#### 15. Grain boundary diffusion (`grain-boundary-diffusion`)

Dy or Tb coated on the surface seeps along grain boundaries.[^21]

- In: Sintered block, Dy or Tb metal. Out: High-coercivity block.
- Key numbers: Diffusion 900 °C[^21]; Coercivity gain 350 kA/m[^21].
- Who does it: JL MAG Rare-Earth, Shin-Etsu Chemical.
- Country concentration: monopolized: 🇨🇳 China ~94%[^7] (2024).
- Feeds: `machining`.
- Elements: [Dy](https://actuatorlist.com/metals?element=dy), [Tb](https://actuatorlist.com/metals?element=tb).
- Map: https://actuatorlist.com/manufacturing#step=grain-boundary-diffusion

#### 16. Machining and slicing (`machining`)

Diamond wire saws and grinders cut blocks into rotor segments.[^22][^23]

- In: Sintered block. Out: Magnet segments, Swarf.
- Key numbers: Material yield 55-75 %[^22].
- Who does it: JL MAG Rare-Earth, Shin-Etsu Chemical.
- Country concentration: monopolized: 🇨🇳 China ~94%[^7] (2024).
- Feeds: `coating`, `scrap-recycling`.
- Elements: [Nd](https://actuatorlist.com/metals?element=nd), [Pr](https://actuatorlist.com/metals?element=pr).
- Map: https://actuatorlist.com/manufacturing#step=machining

#### 17. Surface coating (`coating`)

Nickel-copper-nickel plating or epoxy keeps the segment from corroding.[^24]

- In: Magnet segments. Out: Coated segments.
- Key numbers: Ni-Cu-Ni 10-20 µm[^24].
- Who does it: JL MAG Rare-Earth, Shin-Etsu Chemical.
- Country concentration: monopolized: 🇨🇳 China ~94%[^7] (2024).
- Feeds: `magnetising`.
- Map: https://actuatorlist.com/manufacturing#step=coating

#### 18. Magnetising (`magnetising`)

A pulse coil fires once and the segment becomes a magnet.[^25][^26]

- In: Coated segments. Out: Magnetised segments.
- Key numbers: Field 1600-4000 kA/m[^25]; Pulse voltage 450-3000 V[^26].
- Who does it: JL MAG Rare-Earth, Shin-Etsu Chemical.
- Country concentration: monopolized: 🇨🇳 China ~94%[^7] (2024).
- Feeds: `inspection`.
- Map: https://actuatorlist.com/manufacturing#step=magnetising

#### 19. Inspection (`inspection`)

Flux, dimensions and coating checked before segments ship to motor makers.[^26]

- In: Magnetised segments. Out: Rotor-ready segments.
- Who does it: JL MAG Rare-Earth, Shin-Etsu Chemical.
- Country concentration: monopolized: 🇨🇳 China ~94%[^7] (2024).
- Map: https://actuatorlist.com/manufacturing#step=inspection

#### 20. Scrap recycling (`scrap-recycling`)

Swarf and rejects go back to powder or to solvent extraction.[^27]

- In: Swarf, Rejected magnets. Out: Recycled powder, Recovered oxide.
- Key numbers: Plant scrap 20-30 %[^27]; Recycled ~1 %[^27] (estimate, 2015).
- Who does it: JL MAG Rare-Earth.
- Country concentration: no public country split.
- Feeds: `hydrogen-decrepitation`, `solvent-extraction`.
- Elements: [Nd](https://actuatorlist.com/metals?element=nd), [Pr](https://actuatorlist.com/metals?element=pr), [Dy](https://actuatorlist.com/metals?element=dy), [Tb](https://actuatorlist.com/metals?element=tb).
- Loop: scrap returns upstream.
- Map: https://actuatorlist.com/manufacturing#step=scrap-recycling

### Product

Magnetised NdFeB segments, ready to bond into a rotor.

## Sources

[^1]: Wikipedia, "Mountain Pass Rare Earth Mine". https://en.wikipedia.org/wiki/Mountain_Pass_Rare_Earth_Mine (accessed 2026-11-03).
[^2]: USGS, "Mineral Commodity Summaries 2026: Rare Earths". https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-rare-earths.pdf (accessed 2026-10-25).
[^3]: University of Cape Town, "Mineralogical and ion-exchange leaching study of a rare earth element (REE) bearing ion-adsorption clay deposit". https://open.uct.ac.za/handle/11427/30161 (accessed 2026-11-03).
[^4]: Nature Communications, "Adsorption of rare earth elements in regolith-hosted clay deposits (Borst et al., 2020)". https://nora.nerc.ac.uk/id/eprint/529134/1/s41467-020-17801-5.pdf (accessed 2026-11-03).
[^5]: 911 Metallurgist, "Flotation of rare earths from bastnasite ore". https://www.911metallurgist.com/blog/flotation-rare-earths-bastnasite-ore/ (accessed 2026-11-03).
[^6]: MDPI Minerals, "An environmentally friendly sulfuric acid decomposition strategy for mixed rare earth concentrate". https://www.mdpi.com/2075-163X/14/2/185 (accessed 2026-11-03).
[^7]: IEA, "Rare earth elements: executive summary". https://www.iea.org/reports/rare-earth-elements/executive-summary (accessed 2026-10-25).
[^8]: International Islamic University Malaysia, "Flowsheet design and modelling for high purity praseodymium and neodymium by solvent extraction". https://irep.iium.edu.my/129144/ (accessed 2026-11-03).
[^9]: OneMine, "Study of separation of terbium and dysprosium from other REE by solvent extraction". https://onemine.org/documents/study-of-separation-of-terbium-and-dysprosium-from-other-ree-by-solvent-extraction (accessed 2026-11-03).
[^10]: NUS East Asian Institute, "Rare earths and industry: why dependence on China endures (Background Brief 1843)". https://research.nus.edu.sg/eai/wp-content/uploads/2025/11/EAIBB-No.-1843-Rare-earths_China-2.pdf (accessed 2026-10-26).
[^11]: USPTO, "US 10,865,463: Useful method for separating light rare earth elements and heavy rare earth elements". https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/10865463 (accessed 2026-11-03).
[^12]: Case Western Reserve University, "Molten salt electrolysis for rare earth metals (Holcombe et al., 2025)". https://engineering.case.edu/sites/default/files/2025-10_Holcombe_MSE%20for%20REE.pdf (accessed 2026-11-03).
[^13]: RWTH Aachen IME, "Development and research trends of the neodymium electrolysis: a literature review (Vogel and Friedrich, EMC 2015)". https://test.greenmetallurgy.rwth-aachen.de/wp-content/uploads/2025/08/emc_2015_vogel_id_2892.pdf (accessed 2026-11-03).
[^14]: Reuters via Investing.com, "Goldman says West needs over $25 billion investments in rare earths to match China". https://investing.com/news/commodities-news/goldman-says-west-needs-over-25-billion-investments-in-rare-earths-to-match-china-3120910 (accessed 2026-10-26).
[^15]: Vietnam Journal of Science, Technology and Engineering, "Optimisation of calcinothermic reduction for metallic dysprosium preparation". https://vietnamscience.vjst.vn/index.php/vjste/article/view/1220 (accessed 2026-11-03).
[^16]: University of Birmingham, "Development of a pilot scale strip casting system to produce optimised alloys for neodymium-iron-boron magnets". https://etheses.bham.ac.uk/6791 (accessed 2026-11-03).
[^17]: USPTO, "US 11,270,840: Magnet production". https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/11270840 (not opened).
[^18]: USPTO, "US 11,569,012: Method for improving performance of sintered NdFeB magnets". https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/11569012 (not opened).
[^19]: Advanced Magnets, "Sintered NdFeB magnets manufacturing process flow". https://www.advancedmagnets.com/?p=47 (accessed 2026-11-03).
[^20]: PatSnap (CNIPA patent CN1702785A), "CN1702785A: sintered NdFeB magnet pressing and sintering method". https://eureka.patsnap.com/patent-CN1702785A (not opened).
[^21]: TU Darmstadt, "Grain boundary engineering in sintered Nd-Fe-B permanent magnets for efficient utilization of heavy rare earth elements (Löwe, 2016)". https://tuprints.ulb.tu-darmstadt.de/5872 (accessed 2026-11-03).
[^22]: USPTO, "US 11,373,802: Magnet manufacturing by additive manufacturing using slurry". https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/11373802 (accessed 2026-11-03).
[^23]: Radial Magnets, "Magnet machining and finishing". https://radialmagnet.com/magnet-machining-and-finishing/ (accessed 2026-11-03).
[^24]: Radial Magnets, "Neodymium magnet block N35SH, 1 x 1 x 1 inch (Ni-Cu-Ni plating)". https://radialmagnet.com/our-magnets/neodymium-magnet-block-n35sh-1-x-1-x-1 (not opened).
[^25]: USPTO, "US 7,324,320: Device and a method for magnetizing a magnet system". https://patents.google.com/patent/US7324320 (accessed 2026-11-03).
[^26]: MDPI Sensors, "Impulse magnetization of Nd-Fe-B sintered magnets for sensors". https://www.mdpi.com/1424-8220/16/4/569 (accessed 2026-11-03).
[^27]: Critical Materials Institute (Idaho National Laboratory), "Recycling of NdFeB magnets (research poster)". https://am.inl.gov/SiteAssets/Research%20Posters/CMI%20Recycling%20of%20NdFeB%20Magnets%20final%20(1).pdf (accessed 2026-11-03).