Masdar scientists seek alternatives to rare earth metals

Masdar Institute academics are seeking replacements for the materials widely used in technology, a market China dominates, Daniel Bardsley writes.

Masdar Institute’s Dr Mamoun Medraj is seeking alternatives to rare earths. The ramifications of his research could be hugely important for Emirati business and commerce. Delores Johnson / The National
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Rare earths are used in all sorts of technology – from smartphones and flatscreen televisions to hybrid cars, wind-turbine power systems to communications equipment. They are crucial to many types of equipment we take for granted.

The 17 metals, mostly heavy and found at the bottom of the periodic table, are useful in a wide range of technology including electronics, fluorescent lighting and communications.

Combined with other elements they may be highly conductive, magnetic or able to produce light.

But their ubiquitous use has brought with it concerns over the supply of these elements.

It is not that they are especially rare – more that they tend not to be concentrated in the Earth’s crust, so extraction is often not commercially viable.

China’s iron-mining industry yields them as a by-product. Partly as a result of this, and what some consider more lax environmental rules over extraction, the country has come to dominate global supply. For some elements, it has a market share of more than 95 per cent.

Such dependence raises worries about security of supply, which has driven research into developing alternatives for them.

Among those focused on this are two scientists at the Masdar Institute of Science and Technology – Mamoun Medraj, a professor of materials science and engineering, and Dr Ahmad Mostafa, a post-doctoral researcher.

Among priorities is finding new combinations of chemical elements that have magnetic properties and are resistant to stresses such as high temperature.

One strand of their research involves metals and alloys that are available locally and are relatively inexpensive, including iron, aluminium and manganese.

New mixtures of elements could replace rare-earth magnets, said to be the strongest type of permanent magnet available.

The Masdar researchers are particularly interested in developing magnets that could replace the most common form of rare-earth magnet, namely those that contain neodymium, which is used in an alloy also containing iron and boron.

One drawback of magnets with neodymium is that they are stable up to only 150°C, while some applications can involve temperatures higher than this.

Dr Medraj’s work involves two main steps. First, high-throughput screening to identify promising compositions is carried out.

Then the physical properties of the compositions are analysed, including the magnetic energy product, which is a measure of the magnetic energy generated.

The economic value of the magnetic materials is proportional to their energy product, according to Dr Medraj.

Also measured is the Curie temperature, the point at which a sharp transition in magnetic properties occurs.

Dr Medraj used these screening methods with his research group at Montreal’s Concordia University, where he worked before joining Masdar. The techniques allow new combinations of elements to be analysed and screened in just a couple of months.

Reaching the market will take a lot longer but the faster screening process allows more substances to be analysed.

“The magnetic energy product of the new material that we are developing will range from medium to high,” said Dr Medraj, adding that most of the materials they developed would have a medium energy product.

But “some will have a high energy product comparable to some of the best known magnets”.

New magnets with a medium energy product are likely to be fully characterised and ready for commercial applications within two to three years. For high-value magnets, it is likely to take four to five years.

The magnetic materials Dr Medraj and his co-researchers are looking at are not for domestic purposes but larger-scale applications, including motors and generators for the power industry, such as with wind turbines, and motors used in cars.

Modern cars have many small motors that do things such as opening and closing windows.

Permanent magnets are also important for defence, being used in weapons, satellites, and manned and unmanned aerial vehicles and fighter jets.

“This research will lead to the development of new materials that could significantly reduce the cost of producing magnets, which are critical to the UAE’s aerospace, energy and defence industries,” said Dr Medraj.

Other researchers are focused on using microscopic nanoparticles containing elements such as cobalt, iron and carbon with magnetic properties in powder form.

An additional strategy to eliminate the dependence on magnets made from rare earths is to use flywheels, which use heavy revolving wheels to harness energy and create a power reserve.

Among the scientists interested in their applications is Prof Keith Pullen of City University London, who is researching flywheels that can be used in buses to store energy when the vehicle brakes, and release it when it accelerates. But they have many applications beyond buses and cars.

“You just use steel – there’s no rare earths or anything,” said Prof Pullen. “There’s a whole industry that’s going to be massive in the future – energy storage for the grid as well as vehicles.”

He said flywheel technology could be particularly useful in places such as Abu Dhabi, where there has been expansion of renewable-energy but where the high temperatures complicate the operation of standard batteries used to store energy.

Another advantage highlighted by Prof Pullen is their long life – about 25 years. They could, he said, even be used by individual homeowners to store energy.

But some analysts say rare earth shortages are unlikely despite concerns over China’s dominance of the market.

Prof Andrea Sella of University College London said there was a panic that drove up prices of rare earths but they could ultimately come down, partly because the increased costs had driven “an extraordinary amount of innovation” in battery technology.

“It’s interesting, this interplay between a mixture of geology, chemistry and geopolitics.”

Daniel Bardsley is a UK-based freelance journalist and former reporter at The National

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