Chethana Janith, Jadetimes Staff
C. Janith is a Jadetimes news reporter covering science and geopolitics.
Rare earth metals are becoming more and more in-demand as we move toward a clean energy future, but the distribution of these metals means that their extraction can be incredibly damaging.
Right now, however, we need these materials. So, we need options for viable mineral deposits that can be mined while keeping the side effects to a minimum.
A group of scientists has a proposal for exactly that - extinct volcanoes.
‘Rare earth metals’ is a phrase you’re probably going to hear more and more in the coming years. They’re a class of minerals that we use in a lot of important tech, ranging from cell phones to electric car motors. Slowly but surely, we are becoming ever more dependent on these metals.
But as useful as they are, there are serious problems with rare earth metals. They are difficult to mine due to their typically low concentrations (though deposits are fairly widespread), the mining process produces significant amounts of toxic and radioactive waste, and they are - much like oil - able to be leveraged in sociopolitical situations to an uncomfortable degree. To dramatically undersell it, the whole thing is a total mess.
Unfortunately, however, it’s not really a mess we can extract ourselves from right now - especially considering that the alternatives to certain pieces of rare earth metal-powered tech aren’t great, either. While engineers are working to develop technologies that don’t rely on these minerals, that work is not moving fast enough, and we still need rare earth metals if we are going to transition to a desperately necessary green energy future.
So, if we can’t get away from them just yet, we need options. Right now, experts are hard at work searching for sources of rare earth metals that are both economically viable and can be extracted with limited negative consequences. And one team of scientists has an idea of where we should be looking: extinct volcanoes. They recently published a paper on the subject in the journal Geochemical Perspectives Letters.
“There is an enigmatic type of magma that contains unusually large amounts of iron,” Michael Anenburg, one of the authors of this new study, wrote in an article for The Conversation. “It is so rare, no eruptions featuring this type of magma have happened in recorded history. Instead, it is only known from extinct volcanoes that were active many millions of years ago.”
One of those volcanoes, Anenburg writes, is called Kiruna. Located in Sweden, the site - which has long been mined for the iron in its iron-rich magma - was found to be the “largest rare earths resource in Europe” just last year.
So, the scientists started to wonder if there was any association between the iron-rich magma and higher-than-average concentrations of rare earth metals. In order to investigate, they took on an extremely elevated and complex version of potentially the most well-known science experiment ever, they made a model volcano.
Now, this was much more complicated than the average baking soda-and-vinegar volcano you’d see at a kids’ science fair. To simulate their dead volcanoes, the team built a machine called a piston cylinder. Then, they placed synthetic materials “akin to volcanic rocks and magmas into small capsules or ‘bottles’ made of noble metals such as platinum,” pressurized the entire system to match the conditions found about 9.5 miles (15 kilometers) under ground, and cranked the heat up to about 2,000°F (1,100°C), melting everything into synthetic magma.
Upon examining their super-heated sludge, the team found that little pockets of iron-rich magma formed inside the more standard-issue magma. Even more interestingly, the iron-rich magma appeared to act almost as a sponge for rare earth metals, pulling them in and soaking them up before separating from the normal magma due to differences in density.
“Iron-rich magmas absorb the rare earths so efficiently, their rare earth contents are almost 200 times greater than the regular magmas around them,” Anenburg wrote. “This means the discovery at Kiruna wasn’t an accident. It’s something we can expect from most, if not all, iron-rich volcanoes.”
If they’re right, it means we suddenly have a lot of new, accessible targets for rare earth metal mining - ones that could be pretty good options all-around. Many of these dead volcanoes are already being mined for iron, and could theoretically be adapted for rare earth metal mining without the same trouble as starting up a new mine. According to Anenburg, this would give existing mines new value, avoid ripping up land for new ones, and could even lead to the re-processing of mine waste to search for these valuable minerals.
This doesn’t solve all of our problems with rare earth metals. Not even close. We’re still a long way from perfecting the process of acquiring these incredibly useful minerals, and it will take a considerable amount of work and commitment to make this process better for everyone, everything, and everywhere involved. But to get there, we’ll need to take a lot of steps - and as a first step, this discovery certainly has potential.
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