Promethium (Pm) is not mined in any practical sense. It has no stable isotopes, so commercial promethium is produced as a radioisotope product, mainly promethium-147 (Pm-147), through nuclear irradiation and radiochemical separation.
Pm-147 supply is created by reactor irradiation or fission-product recovery, then unlocked by hot-cell chemical separation and purification, then converted into sealed-source-ready material for industrial instruments and niche power applications.
With normal rare earths, you start with bastnaesite or monazite. With promethium, you start with one of two nuclear feed routes:
DOE's Isotope Program describes Pm-147 as being extracted from a plutonium waste stream as a current supply route.
DOE also states Pm-147 will be produced via direct irradiation of Nd-146 in ORNL's High Flux Isotope Reactor (HFIR).
Takeaway: promethium "mining" is really irradiation scheduling + radiochemical throughput, not geology.
In the target route, highly enriched Nd-146 is irradiated with neutrons. The basic nuclear pathway commonly described is:
Nd-146 (n,γ) → Nd-147 → (beta decay) → Pm-147
This is explicitly discussed in peer-reviewed work describing Pm-147 production and yields from Nd-146 irradiated at HFIR.
longer is not always better because Pm-147 can also capture neutrons, which can limit net yield gains beyond certain irradiation windows.
other promethium isotopes (metastable states, different mass numbers) can be created depending on conditions, and those impurities matter for end-use suitability and shielding considerations.
after irradiation, targets must cool and then be handled in hot cells.
Once you have irradiated targets or a suitable waste stream, you still have a bigger problem: separating promethium from everything else.
ORNL and related technical publications emphasize impurity and yield characterization because these are not minor details in isotope markets.
A practical example from the literature: separation of Pm-147 from neodymium target material using extraction chromatography, described as a selective method to prepare larger quantities of Pm-147 from mg-scale targets.
For normal rare earths, "spec" means purity, trace metals, particle size. For Pm-147, "spec" is dominated by:
DOE program materials explicitly frame Pm-147 as a supply that previously depended on reprocessing abroad and is now being produced through controlled domestic routes, with attention on product suitability.
Promethium is delivered as a radioisotope in a controlled chemical form suitable for:
DOE's market-entry page for Pm-147 lists these as core application areas, which is also a good proxy for the product forms the program is set up to supply.
For many promethium applications, you do not just ship a bottle of compound. You fabricate a sealed radioactive source and integrate it into an instrument system.
IAEA guidance on nuclear gauges lays out the operational and safety framing for nucleonic gauges and their sources, which is the industrial context promethium fits into.
If you do not have irradiation capacity (or the right positions), you do not have product. HFIR is explicitly referenced in the Nd-146 production route for Pm-147.
Promethium production scales only as fast as separation, purification, QA, and compliant waste handling can scale.
Promethium products typically end up in regulated devices and sealed sources, which adds compliance cost and time, but also stabilizes the market (fewer casual entrants).
Because commercially relevant promethium (Pm-147) is supplied as a radioisotope through nuclear pathways, not mined as a stable element from ore.
DOE's Isotope Program describes current extraction from a plutonium waste stream and an additional route via Nd-146 irradiation at HFIR.
Radiochemical separation and purification (often involving selective chromatographic techniques) performed in hot cells, where impurity management determines end-use suitability.