Non-cryogenic separation of Helium_3 from Helium_4?

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SUMMARY

The discussion centers on the separation of Helium-3 (He-3) from Helium-4 (He-4) and evaluates non-cryogenic methods versus traditional cryogenic cooling techniques. Cryogenic separation is established as the most effective method, utilizing a 4K system or liquid helium dewar, which also helps in removing impurities. While there is potential for using differential membrane diffusion at near-ambient conditions, the consensus is that it is less efficient than cryogenic methods. An industrial approach using high throughput helium liquefiers is suggested as a more effective alternative for He-3 extraction.

PREREQUISITES
  • Understanding of cryogenic cooling techniques, specifically at 4K.
  • Familiarity with helium liquefaction processes and high throughput helium liquefiers.
  • Knowledge of differential membrane diffusion methods.
  • Basic principles of isotope separation and purity requirements.
NEXT STEPS
  • Research the principles of cryogenic separation methods for gases.
  • Explore the design and operation of high throughput helium liquefiers.
  • Investigate the feasibility of differential membrane diffusion for helium isotopes.
  • Examine current advancements in helium isotope enrichment technologies.
USEFUL FOR

Researchers, engineers, and industrial professionals involved in gas separation technologies, particularly those focused on helium isotope extraction and purification processes.

Nik_2213
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IIRC, He_3 is usually separated from much less rare He_4 by cryogenic cooling of gas mix to 'liquid', at which point the mix divides to two phases, one with each isotope...

IIRC, Hydrogen and Deuterium, as gas mix, may be progressively separated at near-ambient conditions by differential membrane diffusion.
Is Helium simply 'too slippery' to practicably resolve thus ?
 
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A quick google scholar search suggests that it might be possible to do it using diffusion.
That said, I would be surprised if it would be better than doing using cryogenically. The latter method is very easy and cheap (you just need a 4K system of some type, it can even be a liquid helium dewar) and has the added advantage that other impurities are frozen out (you usually want your He3 to be very, very clean).
It might be worth it if done industrially, but even then using a modern high throughput He liquefier to liquefy the He4 and siphon off the He3 is probably more efficient. That said, the latter is just a guess.
 
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I know a guy working on this via diffusion. "Engineering nightmare" doesn't begin to cover it. Last I talked to him, his target was to enrich the helium so you'd still cryoseparate it but have a better yield at that phase.
 
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