Helium

Potentially. The largest, by far, source of helium is some gas wells in Texas that are unusually rich in helium. It is fairly simple to separate He from CH4. Helium, unlike most everything else, can be lost from the earth system, by floating out into space.

I do remember that the Texas source was being exhausted, but I don't remember when the projected end was. Certainly in the next 50 years. Europe and Japan recycle their helium used for liquid helium, what happens to stuff used in heliarc welding their I do not know

Josh Halpern

The U.S. used to stockpile helium as a strategic material. The Clinton administration killed that plan -- it was expensive, and I don't suspect that military dirigables are going to come into vogue again. But I'd hate to not have any helium around for spargeing HPLC eluent, or to cool an NMR.

in article snipped-for-privacy@posting.google.com, Ralconte at snipped-for-privacy@hotmail.com wrote on 11/19/04 6:02 AM:

I think it was the Republican Congress that did that, but I am not sure. Helium was considered too much of a waste producte and it was silly to put it back into the ground.

Nuclear reactors may end up being reactivated when heliuym becomes really, really expensive.

Bill

If I'm not mistaken, the helium in the natural gas deposits is from trapping a constant flux of helium from within the earth, which in turn is the product of radioactive decay. So there should always be some helium available from underground deposits, if we simply choose to go get it.

Making it _de_novo_ by nuclear reactions is likely to be more expensive for the foreseeable future.

Besides which, alternatives are available for many applications, such as argon for inert gas applications.

It's a little tricky. For example in many applications it is not only the chemical inertness of He that is a winner but also the thermal conductivity. Argon loses in those cases

josh halpern

in article ZRynd.1268$pr1.52@trnddc07, Joshua Halpern at snipped-for-privacy@verizon.net wrote on 11/19/04 7:28 PM:

Hydrogen is usually used to cool large alternators, not helium. Molecularydrogen has higher heat capacity and lower mass and thus high mobility. Helium is trouble for cooling laser flashtubes because it diffuses through fused silica.

It is the low temperature critical phenomena that make it impossible to substitute for helium.

Bill

Besides which, alternatives are available for many applications, such as argon for inert gas applications.(snip) Some, but not all. Argon will not work for gas shielding on welding aluminum, for instance. The argon shielded arc is too hot and scatters too easily.

I wonder if a partial substitution of hydrogen in dirigibles would be safe.(Suppose around 10% hydrogen/90% helium?). Some recent research indicates that the real problem on the Hindenburg was the aluminized skin more than the hydrogen. Besides, many dirigibles are unmanned and used in unpopulated areas (weather balloons come to mind). We should certainly try to extend our finite supply as long as possible.-Jitney

hydrogen has a huge range for its explosive limits, between 4 and 75 %, see your local msds.

josh halpern

A very long time ago, I THOUGHT that I had indirect evidence that helium would permeate a certain ceramic material in a certain crystallographic orientation at temperatures near room temperature. If this wild conjecture were true, than I calculated that it would be possible to extract Helium from the atmosphere in spite of the very low concentration.

Is the helium supply getting stretched thin today where these old conjectures should be examined?

At the time, there were abundant supplies from certain natural gas wells, but that was quite some time ago.

Jim

in article snipped-for-privacy@enews3.newsguy.com, jbuch at snipped-for-privacy@CUTHERErevealed.net wrote on 11/20/04 8:48 PM:

I do not know how practical such a scheme would be. It would probably be more efficient to liquify air and work with the portion that remained gaseous.

IIRC, the group at Linfield College in Oregon working on field emitters did indeed have trouble with helium diffusing through their glass envelopes. I do not remember whether that applied only to fused quartz or to Pyrex as well. Certainly, higher density glass was the way around that problem.

Bill

Excellent idea to work with "residue" of liquified air.

Interesting recollection of helium diffusion through glass envelopes also.

Thanks,

Jim

Weather balloons are not dirigibles. Dirigibles have rigid internal skeletons, which allows them to be driven at higher speeds than blimps and balloons. (The front end of a blimp will cave in at somewhere around 40 mph.)

If nothing else happens (breakage, filament burnout, etc.) an old TV picture tube will get dimmer and dimmer and lose sharpness as it becomes "gassy". This is caused by diffusion of helium through the glass wall of the picture tube. I'm not sure how susceptible modern picture tubes are to this phenomenon -- thicker walls have been used ever since the introduction of "integral implosion protection" in the late 1960's. Old picture tubes had thin walls and could be _really_ dangerous.

Here's a message someone posted about rejuvenating an old HeNe laser tube by diffusing helium through it's walls. I was amazed that this was posted back in 1992. It seems like yesterday. :-)

The internet existed in 1992?

The classic example of this was Rutherford's proof that alpha particles were He nuclei. He put an alpha emitter on one side of a thin glass envelope and found Helium on the other after some time.

josh halpern

We were doing this in the 1970s when HeNe tubes were comparitively much more expensive.

Josh Halpern

I know that some work was done back in the '80's on using reverse osmosis elements, mostly laminate cylinder windings, to separate various gases. It was found that helium had an anti-plasticizer (embrittlement) effect on the polymer materials involved, mostly cellulose acetate, polysulfone and polycarbonates along with the neoprene and polybutadiene seals and gaskets.-Jitney

in article snipped-for-privacy@sonic.net, Mark Thorson at snipped-for-privacy@sonic.net wrote on 11/21/04 10:10 AM:

Actually, the definition of dirigible implies propulsion and control. Nonrigid airships such as advertising blimps are dirigibles.

Bill

What? Aluminum is usually welded with either Pure Ar or 90/10 mix with He. There are trimixes too that include either hydrogen or even oxygen.