Posted by Mark Halper

Albert Einstein was one of the early fiddlers with magnetic refrigeration.

When we launched our blog here at the Weinberg Foundation two months ago, we told you that our “thorium trail” would wind the world looking not only at safe, alternative nuclear power, but also at the related issues and technologies.

Today we head down the “related” path, as we take a look at a startlingly cold development in the rare earth business.

A quick refresher: The global economy would cough blood if denied rare earths. Despite their name, rare earths are not rare. Manufacturers build them into everything – missiles, radar, wind turbines, magnets, iPods, cars and light bulbs, just to name a few common items. China controls the market and restricts exports, causing price volatility. One reason we pay close attention to them at WF is that they often come from minerals like monazite, which also happen to contain thorium, the substance that promises a safe, alternative nuclear future. Policies and practices in rare earth can thus have a direct bearing on thorium availability and vice versa – as we noted in our blog earlier this week on how to safely extract thorium and rare earths.   

Review over.

We now turn our attention to a promising application that could, in a few years, yield a revolutionary product (I never use the word revolutionary when it comes to technology, so that’s how impressed I am in this case)  – magnetic refrigeration.  If only there were enough affordable rare earth materials available.  More on that – and how one company is getting around the problem – in a minute.

But first, while you’re scratching your head:  Yes, that’s magnetic refrigeration, not refrigerator magnet.

WATCH YOUR MAGNETO CALORIES

Magnetic refrigeration promises to do away with environmentally damaging refrigerant gases, and to drastically reduce the amount of electricity it takes to chill your meat and vegetables. It replaces those ubiquitous noisy, power hungry compressors – replacing them with silent efficient magnets. Some people trace the idea back to Albert Einstein.

The concept is simple:  Expose a certain material to a fluctuating magnetic field within the walls of a refrigerator and it will absorb heat, a property known as the “magnetocaloric effect.” Expel the heat, and your milk stays cold.

And you guessed it, that “certain material” happens to be a rare earth element. At least it is in the case of magnetic refrigeration pioneer Camfridge Ltd based in Cambridge, England, which is using a rare earth element called lanthanum.

But that’s only part of Camfridge’s rare earth story. The other part resides in the magnet that springs lanthanum’s magnetocaloric somersaults.

As people who follow rare earths know, magnet makers tend to use a rare earth element called neodymium, a metal in demand for wind turbines, hybrid cars and electric vehicles, among other markets.

That was the plan at Camfridge. That is, until China tightened already severe restrictions on rare exports and drove up the price more than tenfold in 2011, from around $19 per kilogram to, at one point last year, $244 per kilogram, notes Camfridge CEO Neil Wilson.

“Suddenly, with that spike in rare earth prices, it threw out all the calculations,” Camfridge CEO Neil Wilson told me when I spoke with him by phone recently.

DIAMOND IN THE RUST

Although prices have come down again (nowhere near their low), and China has recently slightly eased export restrictions, the volatility caused obvious problems – including “making our investors nervous,” Wilson said.

Innovation to the rescue!

“Our response to the price spike has really been to try to work to stopping using these neodymium iron boron magnets,” said Wilson.

His substitute material is something as old as traditional magnets themselves, and in fact, as old as the hills, really:  Iron (ferrite) oxide, or as Wilson calls it “fancy rust.”

The move to ferrite-based magnets itself is not innovative, although it is much cheaper.  Ferrite magnets cost about a tenth of neodymium magnets.

The trade-off is that ferrite magnets are also “two to three times less powerful,” says Wilson.

And that’s where the innovation comes in. A less powerful magnetic field induces less of a magnetocaloric effect in the rare earth coolant material – the lanthanum, which is actually a lanthanum silicon alloy

Thus, Camfridge and its partners are busy developing a product that uses a lanthanum alloy that can compensate. As Wilson notes, the ferrite “Puts more of onus on the way you make and process the lanthanum silicon material. We’re focused on making really good lanthanum.” If they improve the lanthanum, they can still have their gem of a coolant.

But isn’t the lanthanum also subject to the vicissitudes and volatility of the rare earth market?

Wilson says that at the moment, that is not a concern. Among other reasons: His product does not require a lot of lanthanum – the neodymium represented a far greater portion of the rare earth materials he was using, he notes.

And in the current developmental stage, “we’re only using tens of kilograms,” an amount that Wilson says “is covered by R&D budgets.”

COOL PARTNERS

One of the key partners in his lanthanum development is German magnetic materials specialist Vacuumschmelze.

Camfridge is working with several other partners as well. Those include refrigerator makers Whirlpool from the U.S., Italy’s Indesit (which sells the Hotpoint brand in the UK) and Turkey’s Acrelik (known for the Beko label in the UK). Imperial College London and the University of Cambridge are also on board. The company is backed financially by venture firm Cambridge Capital Group, and by Cambridge Enterprises,  an investment arm of the University of Cambrdge, among others.

It hopes to show a prototype of its “cooling engine” built into a Whirlpool machine by early next year. The idea is to build a magnetic “cooling engine” that is roughly the same size a today’s gas compressor, making it easier for refrigerator makers to swap out the old for the new.

Wilson thinks that his product could hit the commercial market by 2015, when manufacturers would build it into high end, ultra-energy saving models and cut at least 10 percent off the price of the machines compared to conventional gas compressor models. The rare earth engine would require only one half to two thirds the energy of compressors, one source said.

The Camfridge CEO sees the product eventually going mainstream. The company will have to continue refining its engine and making it small enough and affordable enough before that happens. But if it does, Camfridge will have demonstrated how to work with – and without – the realpolitik of the China-controlled rare earth industry.

Photo: Life Photo Archive via Wikimedia.

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