Hertha Metals magnet-grade iron: FLEXHERS process and 2027 deadline for engineers
Reviewed by Tom Sullivan

First reported on MINING.com
30 Second Briefing
Hertha Metals has produced 99.95% purity (3N5) magnet-grade iron at its demonstration-scale FLEXHERS (flexible fuel hydrogen electric reduction smelting) plant in Conroe, Texas, using fully domestic iron ore and natural gas. The Houston startup says it is the first US producer to meet top rare earth magnet makers’ iron specifications with entirely domestic inputs, addressing a material that currently is almost wholly imported. With US defence manufacturers facing a 1 January 2027 deadline to cut Chinese-origin magnet content, Hertha plans its next Chalyx facility to supply high-purity iron for NdFeB magnet producers.
Technical Brief
- Demonstration-scale facility is located at Conroe, Texas, operated by Houston-based startup Hertha Metals.
- High-purity iron feed makes up roughly 70% by weight of NdFeB magnets in EVs and turbines.
- Current US consumption of magnet-grade iron is “almost entirely” met by imports, according to Hertha.
- CEO Laureen Meroueh frames high‑purity iron as a “least visible” but critical defence and EV material.
Our Take
Hertha Metals’ 3N5 iron purity aligns with its earlier plan to supply 10,000 t/y of high‑purity iron from Conroe, Texas, which in our database is one of the few US‑based magnet feed projects explicitly tied to Department of Defense supply‑chain objectives.
With defence manufacturers facing a January 2027 deadline to cut Chinese‑origin magnet content, the 70% iron weight fraction in neodymium‑iron‑boron magnets means any scalable US iron nitride or magnet‑grade iron output could become a bottleneck or price lever, even if rare earth separation capacity expands on schedule.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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