Rare earth supply chain processes highlight an example of a critical material where innovation is key to creating new supply.
Rare earth supply chains are a commodity group that is getting a lot of attention in the media these days but is still poorly understood by anyone who has not studied chemistry and earth science. Many people consider rare earths to be a term used to describe any relatively rare element needed in new technology. In fact, they are a specific group of 15 elements in Group 3 of the Periodic Table beginning with #57 lanthanum (La) and often referred to as the lanthanides.
Two other similar rare elements occurring in Group 3 are scandium and yttrium. They are often included as rare earths as they are usually found in similar geological host rocks as the Lanthanides while remaining chemically distinct.
Two-sub-groups within the rare earth supply chain have been defined based on their atomic number: the light rare earths (#57-61, lanthanum to Promethium) and heavy rare earths (#62-71, samarium to lutetium). The light rare earths, especially lanthanum and cerium, are always more abundant in any rare earth resource but the relative abundance of lights versus heavies can vary depending on geological context.
Ironically, the rare earth elements are not that rare and occur in a variety of geological environments and minerals, but are rarely concentrated to levels that may justify developing the resource from which to extract them as the main commodity. This is why producing them as a by-product from a resource where they occur with other valuable traditional commodities is increasingly being recognised as a new opportunity. This is how production began in China, where they occur in a resource called Bayan Obo that was developed originally as a large iron ore mining operation in which they subsequently discovered rare earth and niobium enrichment. It continues to be the largest rare earth producer in the world.
Because the 15 lanthanides are very similar chemically, they have always been difficult to separate using traditional solvent extraction technologies. While this can be done, it is a very expensive process involving multiple circuits in a very large facility. But it is very important to achieve full separation because each of the separated rare earths have different properties that allow for their application in a variety of technologies.
The most important application these days are in high strength permanent magnets which are vital for electric motor efficiency especially for electric vehicles. The two most important “magnet rare earths” are the lights neodymium and praseodymium used in the original neodymium-iron-boron magnets.
There are now variants on these high strength magnet compositions to include heavy rare earths notably, dysprosium, which creates heat resistance as well as samarium and terbium. Other applications include lasers, x-ray technologies, colour phosphors, fluorescent lamps, glass, ceramics and polishing powders to name a few, plus potential for many more through more research and innovation.
Rare earths supply chains optimal separation process technology
Where innovation is needed most urgently in order to facilitate establishing new rare earth supply chains outside of China, is in the separation process to simplify it and reduce costs. Some progress is being made both in Canada and in Europe and it is just a matter of time now before an optimal separation process technology is defined.
Avalon Advanced Materials Inc has a lot of experience in what the challenges are in starting a new rare earth supply production from an in-ground bedrock resource. But one of the emerging opportunities that we are excited about is the potential for recovering rare earths from the wastes on closed mine sites without having to do any mining. It is a good example of how the circular economy can be established in the mining industry while also innovating new more efficient extraction processes to apply to the wastes.
Closed phosphate mine site
The opportunity Avalon is looking at is a closed phosphate mine site located in North Eastern Ontario where phosphate minerals were originally recovered for fertiliser applications from a carbonatite intrusion. It is a classic example of a mine developed in the past to produce one traditional commodity where the resource contained many other elements that had little economic interest then, but do today and the mine wastes now represent an attractive opportunity to recover them.
These include rare earth elements, scandium, zirconium and potentially others as carbonatite intrusions can host a variety of metals and minerals of economic interest. Once again, the key will be applying an innovative extraction process to recover the rare earths and scandium from the phosphate mineral apatite while also recovering the phosphate for other applications including crop specific fertiliser products.
There are undoubtedly other similar opportunities where alkaline intrusive-hosted mineral deposits including nepheline syenites were developed for one traditional commodity, or even used as aggregate, where rare earths and other rare elements may now be looked at as opportunities to extract critical minerals from the wastes. The time has come to establish the circular economy for rare earth supply chains, while also facilitating the development of the clean technologies needed to achieve a future low carbon economy.
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