Critical Materials
What are critical materials?
Critical materials are nonfuel minerals, elements, substances, or materials essential to technologes in the clean energy, aerospace, electronics, and defense industries due to their unique properties. Their criticality is assessed based on two main factors:
1. Technological Importance in the Energy and Defense Industries.
2. Supply Chain Disruption
Economic importance and sensitivities to geopolitical instability also play a significant role in determining what’s defined as a critical material. Idaho National Laboratory (INL) is addressing these risks by researching alternative materials, improving recycling, diversifying supply, and promoting domestic production.
Common examples of critical materials include cobalt, dysprosium, gallium, graphite, indium, lithium, nickel, platinum group metals, rare earth elements, tantalum, tellurium and uranium.
Why do we need critical materials?
They are essential for supporting key industries, national security, economic growth, technological innovation, supply chain resilience and the shift towards clean energy.
Critical materials are integral for advanced technologies, such as rare earth elements used in high-strength magnets for wind turbines and electric vehicles. They’re crucial for national defense components in military hardware like jet engines and missile systems and are key to economic prosperity by underpinning industries that significantly contribute to the U.S. economy.
Additionally, they are necessary for the energy transition to renewables leading us to achieve climate related goals and are pivotal in various fields of research and development, driving scientific breakthroughs.
Securing our nation's domestic supply chain
Critical materials are essential for the nation’s clean energy transition. The biggest challenge the U.S. faces is that most of these materials rely heavily on foreign suppliers, which are cause for an unstable supply chain.
Key focus areas
Extraction
Before being able to extract, separate and use critical materials, the first crucial step is characterizing the materials that contain them. Idaho National Laboratory (INL) specializes in assessing mining products (i.e., rocks and ore from deposits of interest) in terms of chemical composition, heterogeneity, habit, texture and association.
Resource characterization
INL has several state-of-the-art analytical instruments to detect, quantify and characterize critical materials in environmental sources, such as ores and water, and secondary streams, such as tailings and recycle streams. INL specializes in characterization of rare earth elements in natural waters where low concentrations and other interfering elements (cations) make their detection very challenging with conventional methods.Â
Mineral characterization
INL has the capability to analyze geologic materials from the hand sample to the atomic scale. These geochemical tests are accomplished through high quality and high-resolution analyses using state-of-the-art techniques and equipment, including thin section petrography, X-Ray diffraction, scanning electron microscopy with energy dispersive spectroscopy, and transmission electron microscopy. These capabilities provide key information for whole rock chemistry and elemental composition needed for ore characterization and chemical separation.Â
Geochemical modeling
Geochemical modeling is an important step in understanding the presence and the sustainable production of a resource. INL has decades of experience evaluating resource production, evolution, optimization, and associated environmental impacts to geology and groundwater. Researchers use a variety of software packages, including Geochemist’s Workbench®, PHREEQC and the open-source Multiphysics Object-Oriented Simulation Environment (MOOSE), developed at INL
Mine of the future
Mines of the future will require the development of new technology (e.g., remote sensing, autonomous mining equipment, the use of advanced computational approaches, and digital twins to ensure that mining is sustainable both environmentally and economically). Technology developed at INL will make significant contributions to this effort. Expertise includes:Â
- Advanced microscopy and spectroscopy, including imaging at Center for Advanced Energy Studies – Materials and Characterization Suite
- Advanced analytics for brine and minerals
- Low-energy beneficiation
- Digital twins for mine process optimization
Material Separations
INL specializes in challenging critical materials separations or extraction from wastewater, mining ore, minerals, etc. Over the years, the lab has built world-class, unique capabilities in separations, including hydrometallurgy, biohydrometallurgy, electrochemical facilitated hydrometallurgy, fractional crystallization, membrane facilitated separations and compressed gas processes, such as supercritical fluid extractions.
Hydrometallurgy
Hydrometallurgy is a liquid-liquid separation process to purify target metals from a complex matrix of undesirable contaminants.
It can be achieved through solvent extraction techniques using a variety of equipment and chemical separation flowsheets. Capabilities include the collection of experimental chemical equilibrium data for complex multicomponent systems, computational modeling and simulation for flowsheet design, and validation within counter-current solvent extraction systems. Among those capabilities are:
- A wide range of separations equipment specific to solvent extraction operations, including mixer settlers, pulsed columns and centrifugal contactors
- Development and testing of multi-stage, counter-current engineering flowsheets using a variety of small laboratory systems that can inform flowsheet design and scale-up
In addition, the laboratory brings expertise in chemistry and separations of rare earth elements, actinides and other metal ions.
Biohydrometallurgy
Bioleaching uses acids or metabolites to solubilize and release metals from a solid matrix, which may be ores or unconventional materials.  Â
Bioleaching may rely on microbial reduction-oxidation reactions of iron and oxidation of sulfidic minerals to produce sulfuric acid, or it may rely on the bioproduction of acidic and/or chelating metabolites, such as organic acids. INL develops processes that use both mechanisms to recover critical metals (e.g., rare earth elements, lithium, cobalt, tellurium) from a variety of resources (e.g., ores, tailings, fluidized catalytic cracking catalyst wastes, phosphor wastes, phosphogypsum, permanent magnet wastes, lithium-ion battery black mass).  Â
Process development is aided by thermodynamic modeling and multi-omic techniques to identify microbial communities, metabolites and proteins responsible for efficient mineral recovery. Fundamental understanding of the mechanisms involved enables the identification of critical process variables. Optimization of the process variables can then be guided by design of experiment modeling, where the targets for the latter are determined by technoeconomic assessment and life cycle analysis. The goal is to develop economically competitive and environmentally responsible approaches for critical mineral recovery. Â
In addition, the multi-omic results enable the development of techniques to monitor performance.
Electrochemical facilitated hydrometallurgy
Fractional crystallization
One focus area is dimethyl ether-driven separations, which remove solids from solutions and solutions from solids. They are accomplished with high selectivity (separation factors as high as 700), low energy cost and much higher energy efficiency compared to state-of-the-art processes, while also avoiding the waste generation of chemical (including base) precipitation. The processes are facilitated by dimethyl ether, a low-cost, low-toxicity, environmentally benign commodity chemical that can be easily recycled (>99.9995%). Application space includes mineral recovery, water treatment and processing of wet solids.Â
Membrane facilitated separations
The laboratory specializes in high-performance polymer membranes and engineered nano-scale materials. Among them are:
- Polymer membranes for selective gas separations of CO2, hydrogen and oxygen separations
- High temperature polymer membranes to separate hydrogen from CO2 (syngas)
- Membranes that use pervaporation and membrane distillation for organic and aqueous solutions
The laboratory also researched water filtration with membranes (nanofiltration, forward osmosis and reverse osmosis), as well as facilitated transport membranes for the separation of ethylene from alkanes (saturated hydrocarbon gases).
Chemical separations
In mineral processing, the initial step after mining includes physical beneficiation, a process during which the concentrated fractions of the element (or elements) of interest are obtained. Then, metals can be brought into an aqueous medium through hydrometallurgical processes.Â
INL developed a clean and efficient solution to unlock one of the largest cobalt reserves in the U.S. This novel method extracts cobalt from minerals like cobaltite, which also contains the toxic element arsenic. Through an energy-efficient, low-temperature electrochemical process, arsenic is separated and immobilized as an inert mineral (scorodite). Â
The environmental hazards associated with groundwater contamination are thus eliminated, unlocking the potential value of cobaltite minerals.
Advanced manufacturing
INL develops new advanced manufacturing processes and technologies to reduce the life-cycle energy consumption of manufactured goods and ensure critical material supplies. The processes and technologies apply to metals, alloys and components production. They are used in steel decarbonization, carbon-based material manufacturing (graphite), carbon fiber and carbon matrix composites (carbon-carbon), etc. INL capabilities include:
- Energy efficient low and medium temperature metal production in non-aqueous systems
- Advanced sintering techniques that can be used to make high-performance magnetsÂ
- Robotic separations to beneficiate primary and secondary critical material streams
Metal formation
Metallic materials like neodymium and dysprosium are critically linked to many advanced technologies, including the clean energy sector. Often, these materials are prepared from compounds found in the environment, such as oxides. These oxides are subjected to two operations: reduction and refining to convert them to their metallic constituents.
INL possesses two capabilities for metal formation:
- Rare-earth electrochemical metallization in organic electrolytes (iREEM)
- A molten salt capability for one-step manufacturing of metallic materials directly from oxide intermediates
iREEM is a unique capability that allows researchers to investigate, design and develop environmental-friendly, sustainable, efficient and cost-effective processes for producing rare-earth metals.
Advanced sintering
Sintering is used to press powders into solid objects, such as magnets. INL has unique capabilities for electric field assisted sintering:
- Continuous electric field assisted sintering (CEFAS): one-of-a-kind roller spark plasma sintering system that uses electrical joule heating to locally heat rollers, or the sample directly, and compress material that pass through. Compared to a traditional furnace, the process is extremely energy efficient and allows localized heating.
Large format electric field assisted sintering (EFAS): the electric field assisted sintering press – the world’s largest format EFAS system experimentally available. The system uses joule heating to directly heat the sample/mold ensemble 70% faster than hot pressing and is suitable for difficult-to-consolidate materials, including refractory metals, carbides, nitrides, borides and oxides. The press can process composite materials performing unique joining operations.
Robotic separations
INL has two artificial intelligence-powered automated sorters that can be trained to identify objects based on unique visual and spectroscopic signatures. These sorters are equipped with visual, near-infrared, mid-infrared and 3D cameras, and refractory X-ray fluorescence spectrometer that can identify specific items or items enriched in certain elements. Following identification, automated sorting systems mechanically or pneumatically pick out the desired items.Â
Watch the sorting system in action in this video.
Crosscutting research
Crosscutting research within the critical materials program studies the environmental impacts of critical materials and of their processing.Â
INL researchers also support critical materials research by providing tools and systems engineering to quantify economics and supply chain analytics. Â
Environmental sustainability
Environmental impacts are being assessed by studying microbial interactions with critical metals and processing agents.Â
Studies involve biogeochemical interactions of microorganisms and critical elements, in particular, rare-earth elements. The microorganisms studied perform important functions for wastewater treatment and biogeochemical cycling of nutrients in the environment.
Supply chain analytics
INL has strengths in market and supply chain analytics, operational tools and qualitative assessments for critical materials.Â
INL’s tools have diverse applications, including supply chain analysis, geospatial analysis, market adoption based on technology maturation, production capacity planning, risks and reliability analysis, and environmental-socio-economic impact analysis. Dynamic simulations include system dynamics, agent-based modeling, geospatial analytics, operations optimization and digital engineering. These can either be standalone models or web-integrated models with an applicable dashboard. Â
Techno-economic assessment, life cycle analysis, criticality assessment, risk assessment and road mapping are some of INL’s major quantitative tools.Â
Learn more about our work
Breaking down recycling challenges, one slice at a time
INL researchers are working to solve the pizza box-recycling problem. A recent study shows how to decontaminate cardboard using material separation capabilities.
Trash to Treasure: Sustainable recycling of electric vehicle
INL aims to make the recycling of lithium-ion batteries easier, more efficient, and potentially greener.
Sustainable e-recycling process economically competitive with...
INL developed process that may offer a way to affordably recover precious metals from electronic devices.
