The time has come for me to post a question that has plagued me for many a year. Chances are it’s a silly question, but I’ll feel better knowing the answer.
How do they get just helium into a tank? How do they get a gas into pure form in the first place? Is it found? Is it broken out of more complex molecules? Chemistry was never my strong point, and the last time I took any was my junior year in high school.
I’ve been wondering this for a long time, and can’t find anything about it (maybe because I don’t know how to phrase the question succinctly and descriptively enough for a good online search).
Can’t answer for Helium for sure, but a lot of gases are removed from the air by fractional distillation. The air is compressed and cooled (a lot!) until it liquifies. This liquid is then allowed to warm up (boil). As the temperature rises, the various gases, or fractions, boil at different temeratures. By this method they can be separated from each other.
Once separated, the gases can again be compressed or liquified for storage and delivery.
I’m sure someone will be right here to add or correct anything I left out.
Basically you cool the gas mixture until it turns to liquid. Then you slowly heat it. As each liquid “gas” reaches it’s boiling point, it boils off, changing from liquid back to gas. You pump the gas to storage. Keep heating the liquids and boiling off the different gasses.
In practice, you can do it continuously. Pour the liquid in at one end of a vessel where the temperature varies along the length of the vessel. Put gas outlets at the locations where the liquid is at the boiling point of the gas.
Helium is extracted by doing this to natural gas, which is mostly methane but does have commercial amounts of helium.
I’m sure that the method described by starfish is used for most gasses, but I suspect that for helium it’s a bit different: You cool it until everything else is liquid, and the helium is what’s left. It’s very difficult to liquify helium, and it has the lowest boiling point of any gas, so this is probably easier.
Back to the OP, helium is found, not made, except in fusion reactors (and then in negligible amounts). Helium is one of I think only two elements now that has not ever been put into a compound in the laboratory, and there sure as heck aren’t any natural helium compounds.
I assume that in fractional distillation for helium production, they don’t actually liquify the whole thing. Helium has an extremely low boiling point, if I recall correctly, so it would take a lot of energy to liquify it. They probably just chill until everything but helium condenses out.
And for the record, most helium here on earth is the result of radioactive decay. Of the three types of ionizing radiation (alpha, beta, and gamma), alpha particles are nothing but helium nuclei, two protons and two neutrons. So we mine for most of our helium.
Not necessarily. Noble gases can be forced into molecules in the lab but they are rarely (perhaps never) seen in nature. Molecules form most easily with the higher atomic number noble gases. XeF4O can be made without much difficulty.
The trouble with making noble gas compounds is creating neutral molecules. Helium floride is not neutral. The only neutral compound I know of that contains helium is helium C60, which is a helium atom inside a bucky ball.
There are molecule-ions, salts, and other unusual compounds made with the 6 naturally occuring noble gases: Helium, Neon, Argon, Krypton, Xenon, and Radon.
And now scientists have made Element 118, which would fall under the noble gas column in the periodic table. But with the minute quantities and short half-life, they had no time to see if they could make any salts with it.
