The switch from fossil fuels to renewable energy is going to need some nifty technology that depends on chemical elements that we have not used much before, and most of these come from minerals in rocks in the Earth’s crust. Five of these minerals stand out as Earth’s potential lifesavers.
1. Bastnaesite
The renewable energy transition requires a lot of electricity produced by movement. Think about how the rotating blades of a wind turbine drive a generator that makes electricity. Or how turbines harvest the energy from flowing water or the ocean’s tides and turn it into electricity. The opposite happens in our electric cars, where electricity stored in the car’s battery is turned into motion. The key part in this movement-electricity switcheroo is a strong magnet. And if you have ever been out looking to buy a strong permanent magnet, then you know they don’t come much better than the neodymium magnet.
Neodymium is one of a group of chemical elements that we call the rare earth elements. Many of these rare earth elements have amazing magnetic properties, and modern permanent magnets in wind turbines and electro motors in electric cars use neodymium and dysprosium, or samarium; all three belong to this group of rare earth elements. Besides their magnetic properties, rare earth elements also have cool optical properties: europium, terbium and yttrium help to create colours in plasma screens and LED lights.
But where do these rare earth elements come from? The mineral that we use most to get of our rare earth elements from is bastnaesite. It was first discovered in the Bastnäs mine in Sweden, hence the name, but this mineral is mostly mined in China. In fact, China has a near-monopoly on the supply of rare earth elements to the rest of world. Given the importance of these elements in the energy transition, other countries are looking for their own sources of bastnaesite or other rare earth element minerals. If you've never heard of this mineral, you're certainly not alone, but bastnaesite is a name to remember. It’s hard to imagine an energy transition without this mineral.
2. Jadarite
Electric vehicles massively reduce the amount of carbon dioxide emitted by our transport, especially if the electricity to charge them becomes greener. And the element lithium allows us to make light but powerful batteries that store enough electricity to drive hundreds of kilometers. Lithium is not a fuel, but an electricity storage medium. Once mined, it can in theory be charged and discharged indefinitely. Lithium comes from very salty brines found in salt lakes high in the South American Andes, or from minerals from the Earth’s crust, like spodumene. But in 2005 geologists discovered the mineral jadarite in vast quantities in rocks deep under the Jadar Valley in Serbia. Initial estimates indicate that there is enough of this mineral there to make batteries for at least a hundred million electric vehicles. And it's bound to appear in many other places too.
Here's a fun fact: when scientists determined the chemical make-up of this mineral, they found it was a sodium-lithium-boron silicate hydroxide. When they looked whether such a material was already known, they found one good match: not in the scientific literature, but in the Superman comics. In fact, jadarite matched the chemical composition of the fictional material kryptonite almost perfectly (it doesn’t glow green though!). While we don’t know whether jadarite would kill Superman, its superpower may give a turbo boost to carbon-neutral driving.
3. Chalcopyrite
As a society, were already using a lot of copper, and a world running on green electricity will need more, not less. Just think about all the cables to move electricity around, for instance the thousands of kilometers of high-voltage cables laid out on the seabed to connect the electricity grids of different countries, or to connect wind parks to the mainland. While copper is recycled well, we still mine ever-increasing amounts of copper - about 25 million tons each year at the moment. And most of this is used for our growing network of cables.
Ancient people like the Celtic and Germanic tribes of Europe had a plentiful supply of copper for their tools, weapons and art derived from rocks containing veins of the pure copper mineral referred to as ‘native copper’. These days we get this shiny versatile metal from rocks containing less than one percent copper by weight. These rocks are mined in giant open cast mines such as Escondida in Chile, the largest open cast mine in the world. And the copper in these rocks is mostly contained in the mineral chalcopyrite. This mineral is a close relative to pyrite, which we also know as ‘fool’s gold’. But this is no fool’s material! Geologists have found that chalcopyrite from some places contains small amounts of the chemical elements indium, gallium and germanium, besides the copper. And that is good news for the energy transition too, because those are high-tech elements that we need for things like next-generation solar panels. So far, we mainly get these elements from zinc ore, and the demand for zinc is not likely to increase very much. If we can get these elements from the copper mineral chalcopyrite, then that can help secure the supply of these critical raw materials for the energy transition.
4. Cobaltite
Medieval German miners digging for silver ore sometimes found ores that couldn’t be smelted properly, or that gave off foul vapours. They thought these ores ‘bewitched’ by a mischievous mythical goblin-like creature named a kobold, who loved to tease humans. When the cause of the bewitched nature of the ore was found - a ‘contamination’ that was in fact a new chemical element, it was named cobalt. For a long time, the only use for cobalt was in the production of a brilliant blue pigment that could rival the expensive blue derived from the rock lapis lazuli. Nowadays, we know it as a crucial element in the cathode of lithium batteries - essential for electric vehicles as well as for our mobile phones and laptops.
Cobalt is extracted from a range of minerals containing also nickel and arsenic, the mineral cobaltite chiefly amongst them. But cobalt is one of the most problematic of all raw materials, because more than half of the world’s supply comes from Central Africa, where its extraction is sometimes linked to child labour and human rights violations by local warlords who benefit from the mines. Cobalt is also found in ores in the deep ocean, but deep-sea mining is itself controversial. While many battery manufacturers have indicated that they aim to replace cobalt in their batteries, this has so far proved to be very challenging and there is currently little prospect of a cobalt-free battery. So, whether we like it or not, cobaltite, (hopefully certified and responsibly-sourced), will likely be a mineral at the heart of the energy transition for years to come.
5. Olivine
So what if these minerals help us create a world without new carbon-emissions? What’s next? What can we do to actually reduce the amount of the greenhouse gas carbon dioxide in the atmosphere back to safer levels? One abundantly available mineral could come to the rescue.
Olivine, an olive-green mineral consisting of magnesium, silicon and oxygen, is probably the most abundant mineral in our planet. The upper mantle, the solid layer of rock starting around 35 km beneath our feet to a depth of about 400 km, is mostly made of olivine. This mineral flows like toothpaste at high pressures and temperatures,, which makes plate tectonics possible. While this deep-seated olivine is inaccessible to us, there are also olivine-rich rocks exposed at the Earth surface, and on the seafloor in places like the Atlantic Ocean. And that is good news if we want to reduce carbon dioxide in the Earth’s atmosphere.
Olivine and carbon dioxide like to react with each other and turn into a new mineral - a magnesium carbonate named dolomite. One ton of olivine can react with 600 kg of CO2, making 1200 kg of carbonate but also 400 kg of silica, a raw material for the cement industry but also, much more excitingly, for solar panels. Once reacted, that carbon dioxide is no longer acting as a greenhouse gas. While the large-scale applications of olivine to remove carbon dioxide from the atmosphere are probably a fairly long way off, promising experiments are already being done to build reactors in which this reaction can be run efficiently. So the mineral olivine is increasingly heralded as the go-to mineral to actively get rid of some of the carbon dioxide in the Earth’s atmosphere.
About the author: Arjan Dijkstra is an assistant professor in Earth Materials at the Faculty of Geoinformation Science and Earth Observation. His research focusses on the minerals that provide the critical raw materials for the Energy transition. He teaches Spectral Geology, and will be leading the Integrated Mineral Analysis course on Geoversity, which focusses on lab techniques such as (imaging) spectroscopy, X-ray diffraction and X-ray fluorescence.
