Oak Ridge National Laboratory just won a 2026 R&D 100 Award for a rare earth separation process that halves the number of stages a plant needs for the same throughput. The two ORNL chemists behind it explain why that has almost nothing to do with the molecule.
Subhamay "Subho" Pramanik, an R&D Associate Staff Scientist, radiochemist and synthetic physical-organic chemist, and Marcy Lamb, a radiochemist in ORNL’s Chemical Separations Group, are two of the four researchers named on NEAREST — the Neutral Extractant Advanced Rare Earth Separation Technology. They walk through why all 15 lanthanides sit within 20 picometers of one another, how two ligands with opposite selectivity beat a single acidic extractant, and why the analytical chemistry nobody sees determines whether any of it actually worked.
Why Separating Rare Earths Is So Brutally Hard
The 15 lanthanides, from lanthanum to lutetium, are nearly identical in size, shape and charge. As Pramanik puts it, their ionic radii differ by less than 20 picometers across the entire series. He compares the problem to reaching into a bowl where everything is microscopic and exactly the same color, and picking out one.
Size is only half the difficulty. Rare earths also carry a high +3 ionic charge, so in water they sit inside a tight shell of solvating molecules. Any chelator designed to pull one out has to beat that hydration energy with its own encapsulation energy — which is why ligand design, not brute force, is where the separation is actually won.
Counting Teeth: How Ligand Design Works
Pramanik describes the chemistry as host-guest matching, and the intuitive unit is teeth. A conventional industrial extractant is bidentate — two binding sites, two teeth. A diglycolamide has three. The tetradentate ligands his group designs have four. Since a rare earth ion can accommodate a coordination number of 12, a ligand with more teeth grips more of the metal, which means higher loading capacity and the same throughput achieved with less chemical.
- Bidentate: two binding sites, the conventional industrial baseline.
- Tridentate: three sites, as in the diglycolamides widely used for rare earth separation.
- Tetradentate: four sites, tuned for the subtle radius differences between adjacent lanthanides.
NEAREST: Two Ligands Pulling in Opposite Directions
Conventional solvent extraction asks one acidic extractant to do all the separating. NEAREST asks two. A lipophilic ligand carrying fatty chains lives in the organic phase; a hydrophilic, water-soluble ligand lives in the aqueous phase. One prefers the light rare earths, the other the heavies, and the process uses the synergy between those opposite selectivities. Pramanik traces the underlying concept back to a Basic Energy Sciences project published in JACS by Santa Jansone-Popova’s group, described there as a tug of war.
Because both ligands are neutral rather than acidic, the process is not governed by pH, and no base is needed to neutralize the extractant afterward. That is what makes the aqueous phase recyclable — and hazardous waste disposal is one of the conventional process’s largest hidden costs.
What "Half the Stages" Actually Means to a Plant
Compared against traditional solvent extraction, Lamb says NEAREST lowers the number of stages needed by roughly 50 percent to achieve the same throughput, though the exact figure varies with feedstock. The significance is not chemical elegance. It is capital equipment.
At industry scale, every stage is a new piece of equipment. It increases the footprint. It includes the pumps, the controls, the solvent inventory, maintenance, capital cost.
Crucially, this is not a rip-and-replace proposal. "We are not asking the industry to throw out the existing solvent extraction playbook," Lamb says. The bet is that better molecules dropped into the hydrometallurgical circuits that already exist can deliver the same throughput from a smaller, cleaner plant.
The R&D 100 Award and the Critical Materials Innovation Hub
NEAREST received a 2026 R&D 100 Award, which Pramanik calls "kind of like an Oscar of innovation." The scale-up work now runs through the Critical Materials Innovation Hub, a Department of Energy hub operating primarily out of Ames National Laboratory and organized into thrust areas with thrust leads. Jansone-Popova is one of them. Pramanik has separately been funded for gallium separation work under the same hub.
For companies, the hub is open: industry can participate under a non-disclosure agreement, either across the hub or within a specific project or institution.
Critical Minerals Are Not Critical Materials
Pramanik draws a distinction the press routinely collapses. Critical minerals are designated by the Secretary of the Interior through the U.S. Geological Survey. Critical materials are non-fuel minerals or elements determined by the Secretary of Energy to carry high supply risk, to have no easy substitutions, and to be essential to energy, national security, innovation and transportation. The lists overlap heavily but are not the same — germanium, he notes, is currently a critical mineral but not a critical material.
The Analytical Half of the Story
Lamb makes the case for the discipline that gets the least attention. "The analytical side is actually the other half of the story," she says. "Without it, you will not even know if the separation is actually working." Every separation experiment has to answer what was recovered, which phase each element preferred, and at what purity — questions answered by sampling both the organic and aqueous layers before and after separation and running them on ICP-OES or ICP mass spectrometry.
Repeatability in this system is genuinely hard. Her team works with high salt content brine solutions carrying hydrophilic ligands — a matrix, as she puts it, that is not normal to most cases. A discrepancy of a couple of percent early on cascades: if you lose it at the beginning, it will not come out at the end.
Why High Purity Does Not Mean Easy Processing
A high-grade feedstock is not automatically a cooperative one. What matters is the full composition, including competing metals. Monazite carries heavy loads of lanthanum and cerium that must be worked around to reach the middle and heavy rare earths — samarium, europium, gadolinium. Gallium arrives as a byproduct buried in far more concentrated zinc or aluminum streams. Pretreatment stage matters too, since a supplier may hand over ore, a pregnant leach solution, or something in between. Even the same feedstock from the same supplier varies batch to batch, which is precisely why the analytical work is load-bearing.
The Workforce Nobody Can Graduate Into
"Separation chemistry is not always a degree that you can graduate with," Pramanik says. The work requires a synthetic chemist, an analytical chemist, chemical engineers to model the process, computational scientists, machine learning specialists, geoscientists, manufacturing experts and technicians — assembled as a team, because no single expertise covers it.
ORNL hosts hundreds of students each summer, from high school through graduate level, paired with mentors. Lamb mentored a CMI Hub-funded graduate student this year and took the group to see MP Materials at Mountain Pass, California — a jump from the half-liter mixer-settlers on her bench to industrial ones. Pramanik visits middle and high schools every other month, and points out that a mobile phone contains more than 25 critical minerals.
Key Takeaways
- Less than 20 picometers: the ionic radius difference across all 15 lanthanides, and the reason separation is the supply chain’s hardest chemistry.
- Roughly 50 percent fewer stages: NEAREST versus conventional solvent extraction at the same throughput, varying by feedstock.
- Stages are equipment, not math: each one carries pumps, controls, solvent inventory, maintenance and capital cost.
- Neutral beats acidic: no pH control, no neutralizing base, and a recyclable aqueous phase.
- Drop-in, not rip-out: NEAREST is designed for the hydrometallurgical circuits industry already operates.
- Still pre-commercial: a patent and a couple of license agreements exist, but optimization and scale-up continue, and no NEAREST paper is published yet.
What is NEAREST?
NEAREST, the Neutral Extractant Advanced Rare Earth Separation Technology, is a solvent extraction process developed at Oak Ridge National Laboratory. Instead of one acidic extractant, it pairs a lipophilic ligand in the organic phase with a hydrophilic ligand in the aqueous phase. The two have opposite selectivity, one favoring light rare earths and the other heavy, and the process exploits that synergy to cut the number of separation stages by roughly half. It won a 2026 R&D 100 Award.
Why are rare earth elements so difficult to separate from one another?
The 15 lanthanides are nearly identical in size, shape and charge, with ionic radii differing by less than 20 picometers across the whole series. They also carry a +3 charge, making them heavily hydrated in aqueous solution, so any chelator has to overcome that hydration energy to pull one out.
Why does cutting separation stages in half matter?
At industrial scale each stage is a physical piece of equipment, adding footprint, pumps, controls, solvent inventory, maintenance and capital cost. Halving the stages makes the plant smaller and cheaper to build and operate, and because NEAREST uses neutral ligands, the aqueous solutions can be recycled rather than disposed of as hazardous waste.
What is the difference between a critical mineral and a critical material?
Critical minerals are designated by the Secretary of the Interior through the U.S. Geological Survey. Critical materials are non-fuel minerals or elements determined by the Secretary of Energy to have high supply risk, no easy substitutions, and to be essential to energy, national security, innovation and transportation. The lists overlap but differ. Germanium, for example, is currently a critical mineral but not a critical material.
Can industry work with the Critical Materials Innovation Hub?
Yes. The CMI Hub operates primarily out of Ames National Laboratory and is organized into thrust areas with thrust leads. Companies can participate under a non-disclosure agreement, either in the hub broadly or in a specific project or institution.
Is NEAREST commercially available?
Not yet. ORNL holds a patent and, per Marcy Lamb, a couple of license agreements, but the process is still being optimized for scale-up. No peer-reviewed paper on NEAREST has been published. The underlying two-ligand tug-of-war concept came from a Basic Energy Sciences project published in JACS by Santa Jansone-Popova and colleagues.
Transcript
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Dustin Olsen (0:10)
Hi Marcy, hi Subho, welcome to the Rare Earth Exchanges Podcast. How are you guys doing?
Marcy Lamb (0:15)
Good. How are you?
Dustin Olsen (0:18)
Good. We are excited to have yet another national lab here on the show with us — Oak Ridge National Laboratory. Subho, you are the R&D Associate Staff Scientist, radiochemist and synthetic physical-organic chemist at ORNL. And Marcy, you are a radiochemist and technical associate at ORNL. We are excited to hear your perspective and the work that you are doing at this national lab. So to kick us off: lanthanides sit next to each other on the periodic table and are almost chemically identical. For someone who has never set foot in a solvent extraction plant, why is separating them from one another so brutally hard?
Subhamay Pramanik (1:17)
Yes, I absolutely agree with you. That is the main goal of separating rare earth elements. The lanthanide series, from lanthanum to lutetium — all these 15 elements belong to this rare earth family, along with scandium and yttrium. If you look closely at the lanthanide series, they are almost similar in shape and size. So they are a really grueling challenge to separate into individual streams. If you think about their ionic radius, there is a less than 20 picometer difference between them, which is a very tasking job. I can give you an example. You can think about a big bowl of microscopic [particles], all of the same color — it is very hard to differentiate or distinguish them individually. That is where we are asking the chemistry to do this separation of adjacent rare earth elements. Along with that, they are similar in size and shape, and they also have a high ionic charge — plus three — compared to the transition metals, which also makes it harder to separate from aqueous solution. Because here it comes as hydration energy. Suppose you are separating those rare earths from the aqueous solution: because of the high charge, they are highly solvated by the water molecules, so hydration energy is high. As an organic chemist, I think about it this way: when we synthesize a ligand or a chelator — meaning something that can bind the metal, the lanthanide, and pull it out of the water — the chelation energy, or the encapsulation energy, has to compete with the hydration energy. That is why it is harder. One point is the charge, and the other is the similar size — less than 20 picometers of difference across all 15 elements.
Daniel O’Connor (3:27)
That is fascinating. Is that what you are focusing on today? You had mentioned ligands. Can you speak a little bit more about that — what you are doing there at the lab?
Subhamay Pramanik (3:44)
Yes, definitely. As an organic chemist, I always have a synthesis design in my mind — a kind of chemical intuition about which materials or ligands might work. Suppose we are making a molecule or material which has binding sites. It is a kind of host-guest chemistry: if you have a perfect fit between host and guest, then you can pull out this metal. For instance, I have some models here to show you. This is a ligand — it has red colors, and those are the oxygens, the coordination sites. If you think of them as teeth, it has four teeth to bite the metal and separate it. And suppose I have another one, a DGA — a diglycolamide — which is widely known for separating rare earth elements. This has three oxygens, three teeth to separate those metals. And I also have a different one that has nitrogen and oxygen — the bis-lactam-phenanthroline, or bis-lactam-bipyridine. Those are the conventional names of the ligands, or molecules, which act as chelators. So this one has four teeth, meaning tetradentate. If it has three teeth, tridentate. By tuning that number of teeth, or binding sites, we are trying to elevate the separation between those closely spaced rare earth elements, which have very subtle differences in their ionic radius.
Dustin Olsen (5:35)
So with this process you are describing, how many stages does it go through for you to successfully separate the metal?
Marcy Lamb (5:49)
So, Subho was describing the ligands that we are currently using in our NEAREST technology process — that is our Neutral Extractant Advanced Rare Earth Element Separation Technology, which we are developing here at ORNL. With this, like he was saying, we have a lipophilic ligand in the organic phase that we use with a hydrophilic ligand in the aqueous phase to improve selectivity for group separations of these rare earths. Unlike traditional processes, which just use one acidic extractant, we are not asking just one ligand to do all the separation. With NEAREST, using two different ligands that have higher selectivity for different rare earth groups, we can lower the stages needed to achieve those separations. Right now we are comparing our NEAREST technology with the traditional solvent extraction process, and we can see that we can lower the number of stages needed by roughly 50 percent, because of the higher selectivities with these ligands.
Dustin Olsen (7:03)
That is amazing — 50 percent. But for those who are, we will say, unaware: what does that actually mean? What does a 50 percent savings look like? What is the number of steps we end up using to get there?
Marcy Lamb (7:18)
When we say half the stages, we are talking about the number of individual extraction and separation steps required to achieve the same throughput as the conventional solvent extraction process. This varies, right — depending on the feedstock and things like that, it can vary. But this is huge, to be able to cut these stages, because at industry scale every stage is a new piece of equipment. It increases the footprint. It includes the pumps, the controls, the solvent inventory, maintenance, capital cost. So if we can accomplish that same separation with fewer stages, we are potentially making the entire process smaller. With the NEAREST technology, we are not asking the industry to throw out the existing solvent extraction playbook. We are thinking outside the box chemically with this process. By changing the chemistry to get more separation out of each stage with our ligand designs, we are able to achieve the same throughput with lower chemical consumption — because our binding ligands can extract more than the conventional ones in each stage. And with our ligands being neutral, this also changes the game, because we are able to recycle our aqueous solutions in this process, which is huge. This is another challenge in the conventional process — with all that chemical consumption also comes high hazardous waste disposal. So being able to recycle our solutions is a big game changer.
Daniel O’Connor (9:13)
We are not scientists ourselves. We are trying to make science a little bit more available and cool, so that more people get interested. But it sounds very powerful. It sounds like you have innovated, in a chemical way, how to separate these elements — at potentially 50 percent the effort of the traditional approach. And that is massive. And to your point, from an environmental standpoint, that is a big part of the problem — separation today is not very environmentally good. So would this process involve the use of the same chemicals, just smaller amounts? Or are there different chemicals?
Marcy Lamb (9:59)
They are definitely different chemicals. I will let Subho chime in — he is the guy behind the designs of these amazing ligands that we are currently using.
Subhamay Pramanik (10:08)
Thank you, Marcy. We are using two different ligands, as Marcy already explained. One is lipophilic. If you think about solvent extraction — this is a solvent extraction process we are using, which has been widely used industrially — we have oil and water. Oil is lipophilic, meaning we have a ligand which has lots of fatty chains, which can solubilize in oil. And another ligand or molecule which is more hydrophilic, meaning water soluble. So both ligands have a different selectivity. One is more selective towards the light rare earth elements, another towards the heavy rare earth elements. We are using the synergy of their selectivity, even though we are using two different ligands. And the beauty of using the neutral extractant is that we do not need to be controlled by the pH. We also have a lot more powerful control at the molecular level — we can tune the size, shape, binding pockets, number of donor atoms, and the surrounding anions to recognize the subtle differences between these closely spaced rare earth elements. We are not just minimizing the stages, because each stage is associated with lots of other parameters. We are improving our whole separation methodology. For a conventional solvent extraction process for rare earth elements, they use a bidentate ligand — one ligand has two teeth, kind of like picking up one metal. Usually rare earth elements can have a coordination number of 12, meaning 12 teeth are required to pick up that one lanthanide. We have multidentate ligands, so we can achieve the same throughput using less chemical. And when we have less chemical required, less waste is generated — because we do not need any base to neutralize our ligand after the extraction. In the whole process we are recycling all the solvents, including the reactants, including the extractants, and even the other solutions. So the whole process is much more sustainable and cleaner, so that it can easily be integrated into the existing hydrometallurgical circuits.
Daniel O’Connor (12:46)
Amazing. It sounds really exciting. I think you all put a paper out, if I remember correctly — did you put a peer-reviewed paper out on this yet, or no?
Subhamay Pramanik (12:59)
For NEAREST technology, we have not published a paper yet. But you are right — I think you are talking about the JACS paper. That one, Santa Jansone-Popova published an article based on the Basic Energy Sciences work, where we have shown the tug-of-war technology — kind of like a tug of war, using two different ligands of different selectivity, using the same synergy. Yes, you are right, probably in that concept. NEAREST is more applied, for scale-up. That idea came out of the Basic Energy Sciences project. And now we are working on the Critical Materials Innovation Hub — the CMI Hub — for scale-up. And Marcy is mostly working on scaling up those rare earth separations. And one thing I would like to highlight: recently, our NEAREST technology has been recognized with an R&D 100 Award for 2026. As you know, R&D 100 is kind of like an Oscar of innovation. And we are really proud of this recognition as an R&D 100 award this year.
Daniel O’Connor (14:10)
Congratulations on that. We should publish that for you all — we can get some word out on that. So Marcy, this hub — do you want to talk a little bit more about this hub concept that you are building up?
Marcy Lamb (14:23)
So Subho was talking about the Critical Materials Innovation Hub. Subho could probably explain more in depth about the actual structure.
Daniel O’Connor (14:33)
Or just at a high level — is it something where you are going to have partners? Can industry call and work with you all? Or is it just for scientists, or something companies can collaborate with you on?
Subhamay Pramanik (14:46)
Yes. The Critical Materials Innovation Hub is basically a hub which mainly operates from Ames National Laboratory, and it is funded directly by the [Department of Energy]. This hub has three different thrust areas, and they have thrust leads. Santa Jansone-Popova is also one of the thrust leads. They work on resolving critical material separation, along with the rare earth elements. And recently I also got funded on gallium separation, so we are working on different critical mineral separations under the CMI Hub. Of course, there are a lot of different institutes working, and there is partnership, as you already mentioned. Industry can go under a non-disclosure agreement, and then they can also participate within the CMI Hub, as well as in a particular project or particular institute.
Daniel O’Connor (16:01)
Beautiful. That is good to know. We think there needs to be more academia, national labs, and industry collaborating. Now, we have to elaborate on this quite often — that rare earth elements and critical minerals are not the same. A lot of media will refer to rare earth elements as critical minerals, but they are not. You guys would agree, right, that they are different?
Subhamay Pramanik (16:28)
So, that is the concept — critical materials and minerals. Critical minerals, I would say, are defined as those minerals or elements that have been designated as critical by the Secretary of the Interior — directly from the USGS, the United States Geological Survey. However, critical materials are the non-fuel minerals or elements which have been determined by the Secretary of Energy, or the Department of Energy, to have high supply risk and no easy substitutions, and to be essential for energy, national security, innovation, and transportation. So yes, conceptually they are a little different, because they have been assigned by two different U.S. government sides. But some of the critical materials are also considered critical minerals by the U.S.
Daniel O’Connor (17:28)
Right. I get it — critical materials can include rare earth elements, but critical minerals is a different category. The media intermixes these a lot, and sometimes we try to elaborate, separate, and categorize.
Subhamay Pramanik (17:45)
But I would like to emphasize this: most of the critical materials are critical minerals. Not all the critical minerals are critical materials. For instance, germanium — germanium is considered a critical mineral, but not a critical material right now. Whereas some of the rare earth elements, and also gallium and lithium, those are critical minerals and materials as well.
Daniel O’Connor (18:18)
On that note — I do not want to digress too much, but germanium should be a critical material too. It is very hard to get, it is very expensive right now. So, Dustin, I know we have other questions. I will keep digressing.
Dustin Olsen (18:41)
So I want to go back to your solution, the one we are calling NEAREST. If a U.S. refinery adopted this chemistry tomorrow, does that change the competitive landscape? Or is separation ultimately an operations and scale problem that no molecule can solve?
Subhamay Pramanik (19:08)
Competitiveness is not only about one molecule lowering the cost compared to other countries. The separation performance depends on many parameters. Over the course of our discussion Marcy mentioned feed composition, selectivity, number of stages, throughput, solvent — and also waste generation, environmental footprint, chemical recycling, productivity. Lots of things are deciding parameters for how a separation process can be. The environmental side is very important and crucial for the United States right now, and for us too. So if we can develop highly selective molecules which can selectively separate at the molecular level — that is the root of the separation. From there the separation starts. If we have a liquid-liquid extraction, the separation starts at the interface of these two layers. So we are trying to increase the selectivity by molecular design, so that we can remove a lot of stages, so that we can get by with fewer stages and less acid or less base — that is why we are using neutral ligands. And inevitably we are lowering the solvent inventory. Less waste is generated. The process overall is less, and it makes it more economic. So we should think about chemical separation as a process, rather than only an individual molecule, because there are a lot of parameters associated with it. It can reduce the environmental footprint and make domestic production cleaner and more sustainable by developing this novel technology.
Daniel O’Connor (20:58)
What is really cool about what you are doing is that you are designing both from a molecular approach and also a process approach — innovative ways to do this. What is innovation but doing something faster, or more efficiently, or with fewer inputs? Now, I would imagine there are breakthroughs, and you are probably filing patents on some of these. We have tracked a lot of the need for industrial policy and the lack of workforce. Do you see more chemists and related scientists coming out of colleges? Are you finding that there is more demand in this scientific area for young people?
Marcy Lamb (22:19)
There is definitely a lot more interest at the moment for rare earth extractions. But at Oak Ridge, and within the Critical Materials Innovation Hub that we have been speaking of, we are working hard to provide that next generation of brilliant scientists. For example, over the summer here at ORNL we host hundreds of students, ranging from high school age to graduate students. We provide these internships with mentors — with the smartest scientists in the field here. Giving that younger generation the opportunity to work side by side and get hands-on experience, I feel like it is critical to develop the next generation of scientists coming forward. I actually had the pleasure of mentoring a graduate student this summer who was funded through the Critical Materials Innovation Hub. It was a great experience. Just being able to teach and encourage students is important, I feel like, for the future — and giving them those opportunities. We were even able to take a visit to MP Materials out in Mountain Pass, California. For me that was a huge experience. Working with mixer-settlers in our labs at bench scale, we are up to half-liter mixer-settlers — but to see those large-scale mixer-settlers is just amazing. Giving them opportunities like that, I feel like the outreach is needed.
Daniel O’Connor (23:50)
100 percent. We write a lot about this — there is a need for a variety of engineers and scientists in these supply chains. So it is exciting to hear that there are internships and collaboration with universities, and even high schools.
Marcy Lamb (24:09)
And like you said, it takes us all. It is not just one person to solve the problem. So it is nice to have such a strong field of brilliant people here at ORNL, to work together and collaborate with each other.
Subhamay Pramanik (24:30)
I agree with Daniel. And Marcy already mentioned how we are working on outreach activities. The CMI Hub also provided a toolkit to engage and motivate young minds. I usually go every other month to high schools and middle schools to engage the young minds and help them understand why critical materials and minerals are essential to our energy innovation, and to transportation. Suppose we have a mobile phone — that has more than 25 critical minerals in it. I think we need to understand from the root level. The kids are the future scientists. If they understand the importance, I think it would be very useful and essential. Last month I also went to a summer camp — a SAGE camp organized by ORNL. It gives an opportunity to interact with high school students with hands-on experiments, so they also understand different kinds of magnets, different kinds of chemistry. So it is really engaging. And on the point of separation scientists, I completely agree — because separation chemistry is not always a degree that you can graduate with. So we always work as a team with versatile expertise. For critical material separation, we need a synthetic chemist like me, and then an analytical chemist like Marcy. We also need chemical engineers who would model it. Computational scientists who would give a computational picture before we run the experiments or after the experiments — and there are a lot of artificial intelligence and machine learning people also working. There are geoscientists, manufacturing experts, technicians. So it is all a combined effort to resolve this grand challenge. It is not a cup of tea for an individual person or individual expertise. That is why we are all working together at the lab, and also industry, and also academia, to resolve this grand challenge.
Daniel O’Connor (26:42)
A quick question on that. The computational piece is fascinating. When you are designing new solutions — this is a layperson question — does the computational come first? In drug development, which is an area I sort of come out of, there is AI now being used for discovery of new molecules. Is it similar in this field, where you are using computational models first to see what is possible, and then physical? Or is it the physical first, or both?
Subhamay Pramanik (27:17)
I would emphasize both working together simultaneously. We can start with the computational aspects. Suppose we have an intuition that four or five different molecules can work experimentally — that is intuition. But if we have four or five molecules, then we can go for synthesizing them. If we have tons, 10 or 15 types of molecules, then we have to choose a couple of them to synthesize, because experimentally synthesizing those materials and then implementing them and doing those separation experiments takes a little bit of time. So of course, computational experiments always help at the beginning, but it also works simultaneously as we go further during the experiments. There are a lot of things — intuitions from different experience, and then computational help, along with the experimental results. I think all three pieces work together to develop a feasible technology or feasible solution.
Daniel O’Connor (28:30)
Makes total sense. I know we had a question for Marcy on the analytical side. Can you share more about that — from your role, what areas do you focus on?
Marcy Lamb (28:42)
Maybe the analytical side does not get as much attention as the other side. But the analytical side is actually the other half of the story. Without it, you will not even know if the separation is actually working. You can physically see maybe some color change here and there, but a lot of times you do not. You will say, I got one solution coming out the one side and another one out the other side — but you do not know mechanically what is happening with those phases. So at the end of any kind of separation experiment, we have to answer two main questions. What did we recover? And what phase did the element prefer — and how pure is it? To be able to answer these questions, we take samples from both the organic and the aqueous layers, and we do this before and after separation to determine and understand each element’s movement across the phases. We can do this by using a specialized elemental analysis spectrometer — an ICP-OES or ICP mass spec — to determine the concentrations of each rare earth element in each layer. By knowing the concentrations of the rare earth elements in each layer, this tells us where the rare earth went. And then we can also calculate the purity, the recovery, the separation factors — because this is huge, knowing how these mechanisms work. So by answering these questions: did we extract the right rare earth? Did it go in the right stream? Was it at the right purity? And making sure we can account for all the rare earths in that process, and making sure we are not losing any.
Daniel O’Connor (30:38)
Totally makes sense. I was going to add — from your side, the repeatability. One thing we have learned about this very tricky space is it is almost like an art more than a science. I do not know if that is true, if you all agree — but repeatability is not necessarily guaranteed, is it?
Marcy Lamb (30:59)
No, not at all. And it is very challenging, especially when you are dealing with complex matrices like we are dealing with — the analysis becomes pretty intensive. And like I was talking about, you want to make sure you can account for all the rare earths. Any kind of discrepancy within your analysis can throw your results off big time. You do not know which direction, which element went. So it is really important. We are dealing with high salt content brine solutions, and we also have hydrophilic ligands within our systems — and that is a matrix that is not normal to most cases. So getting repeatability is very crucial with this process, because any couple of little percents off can cause huge problems right down the line. That is what is really important: being accountable for all elements and concentrations throughout your whole process. Because if you lose it at the beginning, it is not going to come out at the end.
Daniel O’Connor (32:06)
One other thing I wanted to address is the material that you first bring in — let us just call it feedstock. It is not all the same. What we have learned is that just because something is high purity does not mean it is going to work with you. And I still do not quite understand it — it is above my pay grade. Even with high purity, you still may not have an efficient process. I have been told things like direction of the mineralization. I am still learning here. Is that true, at a high level?
Subhamay Pramanik (33:05)
Yes, I agree with you. The feedstock is generated from the ores — actual rare earth ores — or sometimes it can be a secondary feedstock, recycling electronic waste. The feedstock is the composition of all the different kinds of metal present in that material or that ore. So mostly pure targeted metal — it does not mean that a lot of competitive metals are not also present along with it. The main target is you have to fish out the targeted one. Suppose we are fishing out a rare earth from a source like monazite ore — you have to fish out the rare earth, and the specific rare earth if you are looking for one, compared to the other competing metals. If you are looking for other metals — suppose you are looking for gallium as a byproduct from a zinc or aluminum feedstock — then you have to fish out the gallium from a whole lot of higher-concentrated other metals. For monazite you also have a lot of lanthanum and cerium compared to the other heavy rare earth elements. So you have to fish out those heavy rare earth elements, or the middle ones — samarium, europium, gadolinium — compared to a lot of light rare earth elements. So highly concentrated feedstock does not mean it would be very easy or that it will facilitate things. There is also a pretreatment — probably you have heard about the pretreatment. And after the pretreatment it can also form the PLS, it is called the pregnant leach solution. So it depends on which stage the industry or the supplier is sharing the feedstock with you. It is very crucial to know the composition and the percentage of competitive metals present. And on top of that, it also depends on the system you work in — from the same industry, same feedstock, the composition also varies. That is why I would say analytical chemists are really instrumental, to give the definitive results. We are glad to have Marcy as an analytical chemist, because you need a very expert chemist so that you can get those definitive numbers at the PPM level — how those elements are present.
Dustin Olsen (35:57)
So I have a question for you guys, and we could probably wrap up the show as we are coming close to the end of our time together. With all the research you are doing, all the advancement that you are seeing yourselves and what you are working on — is there hope for the United States? Is there anything you are truly excited about that we will be able to see at a commercial level that will truly turn the tide, so to speak?
Marcy Lamb (36:31)
Of course, we would love to see our technology implemented in industry to help with the supply chain. It is critical, and to be a part of that would be huge. We are working hard for that direction. We do have a patent, and we do have a couple of license agreements. But like any process scaling up, we still have optimization and some other things we need to fine-tune to get this process the best that we can before that is implemented. But yeah, that would be a huge accomplishment, to see this utilized one day.
Dustin Olsen (37:07)
Subho, anything you want to add to that?
Subhamay Pramanik (37:10)
I just agree with Marcy. And as you have already seen, the Department of Energy is already pushing more funding opportunities for solving this rare earth element separation at industrial scale, and a lot of other critical materials they are focusing on — so that national labs, academia, and industry can all help in developing more sustainable technology for critical material separation. I would love being a part of ORNL and representing ORNL, because ORNL has separation science in its DNA. It is a very strong expertise and infrastructure, including the REDC — the Radiochemical Engineering Development Center — the Spallation Neutron Source, and HFIR, the High Flux Isotope Reactor. Our history actually comes from nuclear and isotope chemistry, and now we are also extending this to rare earth element separation. So I think today we can combine molecular design, computational advanced characterization, radiochemistry, process engineering, and analytical chemistry under the same roof. And the Department of Energy is already pushing for it, so that we can solve this grand challenge. That is all I would say.
Dustin Olsen (38:31)
Perfect. Well said. Thank you guys for being here to share not only your knowledge but your perspective on the work that you are doing. And I agree with you — hopefully one day it would be amazing to see all of your hard work at a commercial scale, truly benefiting the work that we are trying to do as a country to be more self-reliant. But not only here in the United States, but around the world. I think as a global community we could all benefit from more efficiency and being better stewards of the planet that we live on. So hopefully we will have you guys back again on the show to get an update and learn more of what you are doing. This is great. Thanks for being here.
Marcy Lamb (39:16)
Yeah, thanks for having us.
Subhamay Pramanik (39:17)
Thank you for making us part of this Rare Earth Exchanges Podcast. It is a pleasure to be talking with both of you.
