Plasma FIB Webinar
In this webinar we introduce Plasma Focused Ion Beam (P-FIB) which is a instrument that combines a SEM with a plasma-based FIB.
From Rock to Rare Series: Part 2 - Refining
Refining and the Chemistry of Purity
In Part 1 of our Rare Earth Element (REE) blog series, we explored the complexity of mining and the growing landscape of U.S.-based REE production. Now, in Part 2, we move deeper into the supply chain, specifically the refining stage, where the real value of rare earths begins to emerge. As raw earth ore becomes refined REE metals, the stakes for achieving analytical accuracy and trace element purity rise dramatically. EAG Laboratories specializes in helping clients navigate the rigorous demands of REE refining with analytical techniques that go far beyond routine testing.
Refining Rare Earths: The Art and Science of Beneficiation
Before REEs can be used in high-performance technologies, the REE-bearing minerals must be liberated from the host rock, converted into a concentrate, and purified into individual elements. This transformation begins with beneficiation: a combination of mechanical and chemical processes that increase the grade of the ore while separating out waste materials, called gangue, as tailings. Concentrated, mixed rare earths are eventually isolated into individual elements or pairs of elements as oxides or metals.
Beneficiation processes are tailored to the specific ore deposit being exploited; a general example workflow includes:
- Comminution: Crushing and milling the ore to reduce particle size
- Concentration: Separate rare earth-bearing minerals from gangue, yielding a concentrate with 50 – 60 wt% REEs, using magnetic separation, electrostatic separation, and/or froth flotation
- Roasting and acid leaching: Which dissolves the REEs into a solution for hydrometallurgy while driving off elements like fluorine that occur in some REE ores
- Advanced separation techniques: Such as ion exchange, solvent extraction (i.e., liquid-liquid extraction, or electrochemical refining.
- Reduction of precipitated rare earth oxides to metal
The final result of this process is refined, concentrated products like neodymium-praseodymium (NdPr) oxide and neodymium-praseodymium (NdPr) metal.
The Analytical Stakes of REE Refining
REE concentrates can be products in their own right and are often subject to in-house manufacturer analysis and third-party verification at a commercial lab, using tools like X-Ray Fluorescence (XRF) or Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). These techniques ensure buyers and sellers are aligned on major element composition. However, when the product is further downstream, such as NdPr metal, compositional analysis must be far more thorough. Techniques like Glow Discharge Mass Spectrometry (GDMS) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) measure impurities down to sub-part per million concentrations.
Many labs offer routine quality control services, but what happens when a REE refiner or end-user encounters a non-routine problem? That’s where EAG Laboratories can offer deeper value. We excel in specialized applications that require analytical finesse and expertise, such as:
- Detecting impurities at trace levels that could degrade product performance downstream
- Measuring the compositional homogeneity of solid samples (i.e., is the distribution of elements uniform or does it vary with location in a sample?)
- Tracking extraction yields during proprietary separation process development
- Monitoring reagent purity that may affect separation efficiency
- Helping develop a QA/QC protocol that scales with production
- Performing forensic analysis on concentrates and refined metals for traceability and provenance studies
- Comprehensive support and expert consulting to help you understand results
Traceability as a Competitive Advantage
As global demand for ethically sourced materials grows, the traceability of REE concentrates and refined metals is becoming a market differentiator. Using elemental concentration profiles and isotope ratio “fingerprinting,” EAG Laboratories can help mining and refining firms prove the origin of their products. Our experts support companies participating in government contracts, defense supply chains, and ESG-driven investment portfolios. These elemental and isotopic fingerprints can:
- Prevent illicit materials from entering supply chains
- Demonstrate domestic sourcing
- Support claims of ethical mining and refining practices
Importance of this Phase
Mistakes made during refining are costly to revenue and to a producer’s reputation. Poor mineral liberation, undetected contaminants, or inaccurate assessments of concentrate composition can lead to loss of revenue from yield processing, contaminated final products, regulatory setbacks, and customer disputes or rejected shipments.
The refining stage is where precision and purity converge, and EAG Laboratories is uniquely positioned to support clients that demand both.
Further Reading
- U.S. Geological Survey. Rare Earth Elements – Critical Resources for High Technology. USGS Fact Sheet (2002). https://pubs.usgs.gov/fs/2002/fs087-02/
- Scientific Research Publishing. Remarkably Consistent Rare Earth Element Grades at Round Top Yttrofluorite Deposit (2018). https://www.scirp.org/pdf/AMPC_2018010814293996.pdf
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