Helium is one of the few gases that is lighter than air, and more importantly, it is also quite stable, colorless, odorless and harmless, so it is a very good choice to blow a self-floating balloon.
The fact is that in the past decade or so, helium has replaced flammable hydrogen as the most popular balloon gas, but in the past two years, balloons have really not been worthy of helium.
Now helium is often referred to as "gas rare earth" or "golden gas", and the price is soaring, reaching 2,700 yuan per bottle in 2023 (the standard for "bottles" here is between 13MPa-14MPa and a capacity of 40 liters).
Picture: The ratio of balloons to people, 10 inches is almost the size of the penultimate one
"2700 yuan/bottle" is the historical high point of helium prices, if you use such a bottle of helium to blow a 10-inch small balloon, you can only blow more than 600 (data queried online), and the cost of each balloon is still very high.
We usually see helium balloons sold on the street or at the entrance of shopping malls, and sometimes a floating balloon may only cost 5 yuan, so it is estimated that it will not be helium-filled.
Of course, if helium were only used to blow balloons, it would be far less expensive, in fact helium is often considered the only truly non-renewable natural resource on Earth, with a little less, and it has a fairly wide range of uses.
So, the interesting question is, what exactly is helium good for, and why is it non-renewable?
Where does the Earth's helium come from?
Helium is the second most abundant element in the periodic table, in fact, it is also the second most abundant element in the universe, after hydrogen, but helium is indeed very rare on Earth.
This is because helium has zero valency, does not undergo chemical reactions under all normal conditions, and it usually only exists in the form of helium (He), as well as its isotope gas.
At the same time, because it is light, once it appears on the surface of the earth in the form of gas, it will easily escape into space instead of remaining on the earth.
After hundreds of millions of years of escape, there is very little helium left on Earth, but the concentration of helium in the atmosphere can still be maintained at around 5.2 parts per million.
This is because the Earth's lithosphere continuously produces helium to compensate for its escape losses, and as we mentioned earlier, helium doesn't normally react chemically, so how exactly does it come about?
In fact, most of the helium on Earth is the product of radioactive decay, mainly uranium and thorium, which produce about 3,000 tons of helium per year.
This is also the only way helium is currently produced, we can't artificially produce helium through chemical reactions, and once helium enters the atmosphere it escapes – the earth really loses these elements, which is probably why it's considered the only truly non-renewable resource.
The vast majority of the helium formed by natural decay enters the atmosphere and is continuously lost while maintaining the helium concentration, but some of it is trapped in the lithosphere.
The locked helium is usually mixed with natural gas and eventually developed and separated.
According to 2021 estimates, the world's helium reserves are only about 31 billion cubic meters (more than 5 million tons), which is a very rare resource, and it is also quite unevenly distributed, with a third of it in Qatar.
© shutterstock/Anamaria Mejia
What is helium used for?
Balloon blowing is actually the application of helium's low density and inertness, but helium actually has many very good properties, it has very low solubility and high thermal conductivity.
These properties allow it to be used in many applications, such as welding, pressurization and purging.
However, what really makes helium a "golden gas" is its low boiling point, with the critical temperature and boiling point of liquid helium being 5.20K and 4.125K, respectively, which is close to absolute zero and the lowest of all substances.
This makes liquid helium widely used in cryogenics and for the cooling of superconductors.
Figure: Liquid helium
However, it is extremely difficult to liquefy, and after the British physicist Dewar liquefied hydrogen in 1898 (the temperature reached minus 253 °C), all the gases were either liquefied or solidified directly, except for helium, which remained in its gaseous form, and it was not until 10 years later that scientists succeeded in liquefiing helium.
The resistance of some substances will suddenly disappear at low temperatures, this phenomenon is called superconductivity, superconductivity as the name suggests is zero resistance, and its other property is complete diamagnetism, these two properties have made superconductors used in many fields.
Figure: MJMRI
There are some substances that will be superconducting at the temperature of liquid nitrogen, but there are some substances that require lower temperatures, and they need to use liquid helium, and there is no substitute, such as the superconducting materials used in magnetic resonance imaging instruments and the European Large Hadron Collider are cooled by liquid helium.
A medical MRI machine needs almost 2,000 litres of liquid helium to keep the magnet cool enough to operate, and although a lot of liquid helium will be reused, it will still consume some of it, about 1%-2% of the total capacity per day.
Figure: Helium production and production regions in 2023
According to Bloomberg, the European Large Hadron Collider consumes almost 120 tons of helium per week, and the total global helium production in 2023 is only 170 million cubic meters (the density of helium is 0.165kg/m³), so it uses up 23% of helium production.
In fact, as early as 2014, 32% of helium production capacity was used in the cooling sector, and in recent years, as superconductors have become more widely used, this proportion has been increasing, so that other fields have to abandon helium and replace it with other gases.
At last
Due to its industrial applications, it is not an exaggeration to compare helium to "rare earths", but unlike real rare earth elements, China is very scarce in terms of helium resources (China is a major producer of true rare earths).
In recent years, China has consumed more than 20 million cubic meters of helium annually, 85% of which is imported, and as the use of semiconductors and superconductors continues to increase, China's helium demand is expected to increase by 5.8% per year.
However, helium is not extracted like oil, and with the development of extraction technology, the supply of oil has so far been able to keep up with the demand, and even far exceed the demand, while helium will only become rarer.
In the past two years, there has been an endless stream of news about the out-of-stock helium balloons in amusement parks, but it is estimated that in another two years, there will be no more helium balloons.