[Ographer]

The issue is mostly with our refining capabilities. Helium is mixed with natural gas as it travels from wells to compressor stations which push it down the pipeline to the refinery for separation. There are only 14 refineries in the world set up to capture helium, half of which are in the United States.

Building new refineries can take decades and is extremely expensive. The refinery and wells also must be located near radioactive reserves which decay and produce the helium.

You're absolutely right about party balloons not being an existential threat. There are two types of Helium for commercial sale: balloon-grade and Ultra High Purity Grade. Balloon grade Helium is used strictly for balloons and is not adequate to be used as a shielding gas or in any medical capacity. Ultra High Purity Grade has undergone the scrubbing process after extraction, and is safe for welding, industrial and medical applications.

[altacc]

The idea of "balloon-grade" led me down a rabbit hole. It seems that there are many defined grades of He with the majority being grade 5 (99.999% purity, 2 steps down from the purest) and the majority of He used, including in balloons is grade 5 due to ease of transporting just one grade. That made it cheaper to use grade 5 for party balloons than artificially reducing the quality.

In the last few years there has been more low quality balloon grade (97.5% purity) produced by refineries in the US, increasing the availability and reducing the cost.

http://www.kornbluthheliumconsulting.com/wp-content/uploads/... https://zephyrsolutions.com/what-are-the-different-grades-of...

[PaulHoule]

Couldn't you just buy high purity helium and mix in some air close to the point of sale?

[mtoner23]

you're not going to save much cost by doing that 99 -> 97% isnt much difference in helium. the difficulty is not in the quantity of helium but the purity. if you dont care much about the purity it will be cheaper to produce.

[foota]

Isn't the resource being consumed the same though? I imagine ultra high grade is just more refined? Or is the balloon grade gas not economically refinable to the pure gas?

[simcop2387]

Not just non-economical, but like almost all purification processes you will be producing balloon grade from the production of the ultra pure gas. Intrinsicly there will be helium that you can't separate from the other gasses that you removed from the helium.

[foota]

Some non-zero remainder is all but inevitable, but even if your refining process yields 1 part pure to 99 parts mixed, after N steps you have 1 - (0.99) ^ N percent pure gas out of the whole, right?

So the ratio is somewhat arbitrarily (up to whatever the limit of your refining process is).

[simcop2387]

Unfortunately that doesn't usually hold out because as things get closer but not quite to the purity you need, you tend to need longer times, larger surfaces areas, higher temps, etc. in order to continue the process. You tend to hit spots during purification where you end up with an Azetrope (or similar for gasses) where you can't do a lot of the same techniques anymore because the impurities and the gas you want end up behaving the same at that concentration. At that point you have to start looking at adding catalysts or other chemical reactions to destroy or transform the impurities so that you can remove the end products from those reactions. But as you have less and less of the impurities it then ends up harder to target them to purify further. It's a nasty cycle that can drive costs up exponentially in terms of reagents, dollars, time and energy needed to do the purification. Ethyl Alcohol is a fun little rabbit hole to look at, at ~95% purity it forms an azetrope with water and you can no longer distill off the water or alcohol separately and have to resort to chemical or other means to get further purity. That's why you usually end up with other alcohols as a byproduct when purifying further (methanol in particular, since it disrupts the azetrope and lets you boil things off) or have to take rather expensive methods that remove the water.

https://en.wikipedia.org/wiki/Azeotrope

[bananaflag]

This assumes that the refining process works the same no matter what the initial concentration is. (Don't know if it's true or not, but it's an unstated assumption.)

[wonnage]

Balloon gas is already 99% helium. There’s not that much of it (one source is apparently as a byproduct of filling pure helium containers) and reprocessing it is not economical.