Recovering and recycling a critical chemical in research

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The Large Hadron Collider is a particle accelerator that made headlines in 2012 after scientists found a new particle, and won the Nobel Prize in Physics in 2013. That experiment is one of many in physics that rely on liquid helium to function. (Maximilien Brice/CERN)

The Large Hadron Collider is a particle accelerator that made headlines in 2012 after scientists found a new particle, and won the Nobel Prize in Physics in 2013. That experiment is one of many in physics that rely on liquid helium to function. (Maximilien Brice/CERN)

Some physicists are leaving their field because of rising helium prices.

A few years ago, Sophia Hayes, a chemist at Washington University in St. Louis, gave up her salary for nearly two months over the summer in order to pay for her research project.

“Any decrease in salary is always a negative, and yet if it’s the way to keep your research program going, that is what many of us do,” she says. “It’s not bitterly; it’s with a smile and it says, ‘I find that this is so important to me that I will make it work.'”

She studies semiconductors, and her work could be useful for solar energy and LEDs. But her research needs nuclear magnetic resonance spectroscopy, or NMR. It’s related to the MRIs in hospitals, only you use this to look at molecules and chemical reactions.

NMR and MRIs both need powerful magnets, and these magnets need to be very cold. That’s why you need very pure liquid helium, much purer than what’s in balloons. You can never get any colder than absolute zero, which is zero Kelvin.

“Within the sciences, any time you need to get to very low temperatures, you need this resource. There’s no other substitute and nothing that comes even close to these low temperatures of four Kelvin,” Hayes says. “You would give up nearly everything else in your research program before you would allow a magnet to run out of this critical liquid. That means that whatever price it costs, we will pay it.”

Aside from NMR and MRIs, helium is used in physics experiments like the Large Hadron Collider (famous for detecting the Higgs Boson in 2012) and it’s also used in making the semiconductors that go in smartphones, computers, and all modern electronics. But, the price for the very pure gas has more than doubled in the past few years, and that’s a big problem for researchers like Hayes.

She pays for helium using money from research grants, like from the National Science Foundation.

She has to write a proposal, say how much she needs to spend on graduate students, chemicals like helium, going to conferences, and how much to pay herself to keep working over the summer. Once approved, she gets a chunk of money for a few years.

But she can’t go back to the National Science Foundation and say, ‘sorry, the price of helium doubled, can you give me more money?'”

“Think of being in your household, and the price of gasoline triples or quadruples. How would you make ends meet on a budget when you have a fixed amount of money coming in?”

And why does the price of helium keep rising?

Mark Elsesser, a senior policy analyst at the American Physical Society, says “it’s not so much that the world’s running out of helium (it’s the second most abundant element in the universe); it’s that the supply chain for helium is very, very sensitive to any disruption.”

Earlier this summer, Qatar was blockaded by Saudi Arabia and other neighboring countries, leading to two helium plants closing. Qatar is the world’s second largest producer of helium and the biggest exporter, accounting for 25 percent of global demand. The blockade led to some U.S. scientists scaling back their experiments to ration helium, according to Elsesser.

We get helium as a byproduct of natural gas extraction. We don’t store helium above ground, so there are no giant canisters we can just tap if we need more. The one exception is the U.S. government’s federal helium reserve, which is scheduled to close in 2021.

Elsesser says the volatile helium price is affecting what type of science gets done in the U.S.

“There are researchers who are exiting the field of low temperature physics because it’s just become prohibitively expensive for them to have a research group,” he says. “We’re losing our nation’s capacity to do that area of physics.”

Remember, liquid helium is used to keep things cold, so after it does that, it gets hotter and becomes a gas again, which means it’ll just evaporate into space. Some scientists don’t want to see this expensive chemical just disappear, so they made a machine that can take helium gas and turn it back into a liquid.

The University of Pittsburgh has one of these helium recovery systems. The physics labs that use liquid helium have copper pipes to send the helium gas to the “bag room” where there is a 10,000 liter bag of helium. Think of it as a room-sized black balloon.

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Helium gas goes to this big bag before it goes through a helium recovery system so it can be purified, turned back into a liquid, and reused. The University of Pittsburgh saves hundreds of thousands of dollars a year by not having to buy as much helium as they used to. (Alan Yu/WHYY)

The gas from the big balloon goes into canisters, where it’s fed to the helium recovery machine, which is about the size of a big Xerox, and it gets compressed.

Then it goes to another machine, which uses liquid nitrogen to partially cool and purify the helium. It’s then compressed again and expanded, lowering the temperature further.

A portion of the cold gas at each stage circles back around to cool the incoming gas some more. Periodically, water and nitrogen and other impurities get blasted out.

By the time you have liquid helium, it goes into a dewar, which is a big, six-foot-tall silver thermos. By that point, some of the pipes are so cold that there’s a layer of frost on the surface.

The system cost $4 million to build, but the university will recoup that cost in less than 10 years, according to Pete Chambers, director of Shared Research Support Services.

Physicist Patrick Irvin says it’s saving them money — since the system came online two and half years ago, the university has recovered about $200,000 worth of helium. That’s enough money to hire two extra staff members. And he adds the National Science Foundation wouldn’t support them enough to pay for both the staffers and the helium.

He shows me one experiment that he wouldn’t be able to do without a helium recovery system, one where he looks at how electrons move in strong magnetic fields.

“It just uses that much helium: sometimes we can use 300 liters a week…that’s $3,000 per week.”

Other universities have asked the University of Pittsburgh if they can buy the recycled helium, but they’re scientists, not helium suppliers. Besides, the federal rules around funding make that difficult.

Sophia Hayes, who gave up her summer salary to buy helium for her lab, says her school is considering a small helium recovery system too. She says she and her colleagues are “ecstatic.” If all goes well, it’ll be in place in six months or a year.

And there may be more U.S. supplies in the future as well. The House Natural Resources Committee is considering a bill that would allow companies with mineral leases to drill for helium.

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