Rare Metal Technology 2026

Inhaltsverzeichnis

1. Frontmatter

2. Rare Earth Elements Fundamentals, Extraction and Separations

   1. Frontmatter

   2. Processing of Secondaries to Reclaim Rare Earth Metals (REMs): A Review

      Rekha Panda, Rukshana Parween, Ankur Sharma, Manis Kumar Jha

      Abstract

      The rising demand of rare earth metals (REMs) in industrial applications, lack of available high-grade primary resources, and associated supply risks due to geopolitical, environmental, or technological factors have laid emphasis on the development of feasible processes to recover REMs from secondary resources to meet their future requirements. In view of the above, the present paper reports the review on available process flowsheets based on pyro-hydro and hybrid techniques to recover REMs from industrial residues (fly ash, red mud, steel slag, atomic minerals tailings, etc.) and secondaries (Nd-Fe-B, Sm-Co magnets, etc.) and fluorescent lamps. The salient findings of different processes are reviewed and recommendation have been made, which will be helpful for researchers working in the field of REMs extraction and recovery.

   3. Comparative Study of HCl Leaching with and without Microwave Pretreatment for Rare Earth Recovery from Vietnamese Bastnaesite Concentrate

      Wonhong Song, Jihye Kim

      Abstract

      Rare earth elements (REEs) are essential components in modern technologies, including electric vehicles, wind turbines, and consumer electronics. As global demand for REEs continues to grow, there is an urgent need for efficient and diversified extraction methods that minimize reliance on harsh chemicals and high energy input. To this end, this study compares two approaches for REE recovery from Vietnamese bastnaesite concentrate: (1) direct HCl leaching, and (2) microwave-assisted NaOH roasting followed by HCl leaching. These methods were systematically evaluated in terms of leaching efficiency and reagent consumption. Direct HCl leaching was carried out at 25–90 ℃, 2–12 M acid concentration, a liquid-to-solid ratio of 10 mL/g, and 500 rpm. We obtained a maximum REE recovery of 72.41% under 12 M HCl at 90 ℃ for 8 h. In contrast, the microwave-assisted roasting was conducted at 700 W and a NaOH-to-concentrate ratio of 0.1–1:1 (w/w) for 90 s, followed by HCl leaching under the conditions of 2–12 M HCl, 90 ℃, a liquid-to-solid ratio of 10 mL/g, and 500 rpm. Using this method, we achieved 91.86% leaching efficiency with 3 M HCl and 99.38% with 4 M HCl at a 0.2:1 (w/w) NaOH-to-concentrate ratio. These results support ongoing efforts to develop more robust and environmentally responsible REE extraction strategies, contributing to a secure and regionally diversified supply chain.

   4. Extraction of Rare Earth Elements from Coal Ash of Thermal Power Plant

      Shafiq Alam, Toni-Ann West, Sabrina Murodillaeva

      Abstract

      The coal ash of a thermal power plant was leached in nitric acid, and it was found that the pregnant leach solution (PLS) predominantly contains rare earth elements (REEs), such as lanthanum (La), neodymium (Nd), praseodymium (Pr), cerium (Ce), and yttrium (Y). In this research, solvent extraction tests have been carried out using different organic extractants, such as D2EHPA and Cyanex 923 in kerosene, where isodecane was used as a modifier to extract REEs from this PLS. Different operating parameters, such as time, temperature, A/O ratio, feed metal concentration, and extractant concentration, were studied to determine the optimum conditions for maximum extraction of REEs by the extractants. Experimental results revealed that Cyanex 923 performs better than D2EHPA, where about 89% Ce, 77% La, 92% Pr, 93% Nd, and 96% Y were extracted at their optimum conditions.

   5. Hydrometallurgical Extraction of Rare Earths from Nitric Acid Leached Solution of Apatite Using Mixed Organophosphorus Extractant

      Rajiv R. Srivastava, Sadia Ilyas

      Abstract

      Apatite is an important host mineral for rare earth metals (REMs); however, it has received comparatively less attention than other REM-bearing minerals such as monazite, bastnasite, and xenotime. Herein, we present laboratory-scale results on REMs’ recovery from an apatite ore leached solution in nitric acid via solvent extraction using an organophosphorus extractant mixture. Key process parameters like the concentrations of H⁺ and NO₃^– ions in the aqueous phase and the extractant concentration in the organic phase were optimized to achieve maximum extraction of REMs. The results showed that increasing NO₃^– ions in the aqueous phase and extractant concentration in the organic phase enhanced REMs’ distribution into the organic phase. Conversely, higher proton concentration suppressed the extraction efficiency. Additionally, the composition ratio of the organophosphorus extractant mixture exhibited a notable influence on REMs’ extraction. The findings of this study will support the scale-up of the process for recovering high-purity REMs’ salt.

   6. Hydrometallurgical Processing of Waste Fluorescent Lamps Phosphor Dust for Rare Earth Recovery

      Manish Kumar Sinha, Himanshu Tanvar, Brajendra Mishra

      Abstract

      As fluorescent lamps (FLs) are gradually discontinued, recycling end-of-life and stockpiled units becomes essential to conserve the critical rare earth elements (REEs) contained within their phosphor coatings. Recovering these metals supports both sustainable waste recycling and reduces reliance on primary REE supplies. This study details a systematic recycling process for maximal REE extraction. The process begins with separating non-REE phases, followed by temperature-controlled acid leaching to dissolve yttrium (Y) and europium (Eu). Eu was selectively precipitated from the leach liquor as EuSO4, while Y is recovered as a double sulfate salt. The residual solid underwent peroxide fusion, water leaching, and acid leaching to extract lanthanum (La), cerium (Ce), and terbium (Tb). A separation process was established to isolate individual RE-products from the leach solution, involving Ce oxidation-precipitation followed by Tb and La recovery via solvent extraction. A comprehensive flowsheet was developed to reclaim critical REEs from FL phosphor dust sustainably.

   7. Effects of Aqueous Complexing Agents on the Selective Adsorption of Rare Earth Elements by Functionalized Nano Powders

      Easton Sadler, Michael Free, Prashant Sarswat

      Abstract

      The separation and purification of rare earth elements (REEs) is of paramount importance to stabilizing long-term feedstocks of precursor materials necessary for the manufacturing of advanced technologies. The chemical similarity of these elements has required the development of new extraction techniques that take advantage of minute differences in chemical properties. Since the late 1950s and 60s, synergistic effects of diluents and the addition of aqueous complexing agents to selectively suppress extraction have been applied to solvent extraction systems. This research applies the concept of adding complexing agents to a solid–liquid system of nano powders functionalized with trimesic acid adsorbent. The addition of ethylenediaminetetraacetic acid (EDTA) increased competition between REE complexes for the available immobilized trimesic acid extractant sites. This resulted in increased separation between REEs, allowing for purities of individual REEs in a synthetic four-element solution to be above 99% after two stages of loading.

   8. Separation and Purification of Rare Earth Elements Through Adsorption by Functionalized Low-Cost Materials

      Ben Schroeder, Michael Free, Prashant Sarswat

      Abstract

      The separation of rare earth elements (REEs) through traditional means remains one of the primary barriers to meeting current market demands for REEs in critical sectors such as electric vehicles and defense technologies. We propose a new method of REE separation and purification which utilizes functionalized low-cost materials such as cellulose and other common substrates to adsorb dilute REEs in an aqueous solution. The substrate can be functionalized with molecules that exhibit ionic radii dependent adsorption behavior. We demonstrate that with carefully tuned chemistry, high purity lanthanides can be generated in only a few adsorption-desorption cycles from an initially diluted and mixed feed source. We aim to explore the mechanism underlying the selectivity of this material as well as ways that this can be further tuned to optimize metal purity from the process.

3. Rare Earth Elements Processing and Magnets/Lithium Extraction, Processing and Recovery

   1. Frontmatter

   2. Design Criteria for High Temperature Rare Earth Liquid Metal Processing Equipment

      Thomas Villalon

      Abstract

      The processing of rare earth metals and alloys presents many difficulties due to their extreme reactivity and high temperature behaviors. To properly process these metals in high temperature liquid form, special attention must be paid to material selection along with operating parameters to allow the metal to maintain high purity specifications. In addition, the long term behavior of these vessel materials must also be considered due to long term creep, corrosion, and grain boundary effects. A case study will be examined here that incorporates all of these technical aspects: a liquid-metal siphon designed specifically for harvesting rare earths after metallization. The principles of materials selection for high throughput rare earth liquid metal processing will be elaborated upon, primarily in areas of high thermal gradient. This material selection in conjunction with operating controls enables new technologies for next generation metals processing.

   3. Neodymium Metal Production Through Metallothermic Reduction

      Himanshu Tanvar, Brajendra Mishra

      Abstract

      Neodymium (Nd) metal plays a crucial role in modern technology due to its unique magnetic and electronic properties. It is a critical raw material for manufacturing high-strength permanent magnets in wind turbines, electric vehicles and electronic devices. Nd is industrially recovered as oxide, oxalate or halide salt after multistage separation and refining methods applied to the primary minerals such as bastnasite and monazite. The purified product is further reduced to metal suitable for magnet manufacturing. Electro-metallurgical methods presently account for the largest quantities of Nd metal commercially produced. These processes utilized consumable carbon-based anodes and molten fluoride electrolyte, generating effluents with a significant environmental footprint. This study presents a cost-effective and environmentally friendly metallothermic reduction process for producing magnet-grade Nd metal and master alloy. The approach employs sodium metal as a reducing agent in a low-melting eutectic system to recover directly Nd metal and master alloys.

   4. Oxidation Kinetics of Hydrogenated NdFeB Magnet

      Kwangsuk Park, Bosung Seo, Eun Bin Cha

      Abstract

      Pretreatments such as grinding and oxidation play an important role in recovering rare earth elements (REEs) from spent NdFeB magnets in terms of selectivity and efficiency. As high content of iron (Fe) usually results in poor oxidation rate, improving oxidation rate is a critical aspect for recovery of REEs. The hydrogenation process, especially when the temperature was over 750 ℃, which induced both the dissociation of Nd₂Fe₁₄B matrix and hydrogenation of the Nd element, would be a good way in increasing oxidation rate with the growth of Nd₂O₃ particle because the hydrogenated magnet was known to be unstable and easily oxidized. When hydrogenated, the oxidation rate was increased and only 3 h. was needed to obtain full oxidation when hydrogenated at 650 ℃. TG/DSC analysis showed the linear weight gain for the hydrogenated magnet with the lower oxidation temperature. Combined with EMPA results, it can be inferred that the hydrogenated magnet possessed the increased oxygen diffusion paths due to the numerous Nd hydride dispersed in the α-Fe, which allowed the facile diffusion of oxygen and the reduced activation energy. Also, the hydrogenation process provided the improved resistance to the NdFeO₃ formation. The oxidation at 650 ℃ did not induce the formation of NdFeO₃, while NdFeO₃ was formed when oxidized over 700 ℃.

   5. Recycling of End-of-Life NdFeB Magnets Using Sulfation Roasting and Water Leaching

      Pushpa Gautam, Shreyas Prashant Kadam, Jayasree Biswas

      Abstract

      The efficient recycling of rare earth elements (REEs) from NdFeB magnet waste is critical for sustainable resource management. This study investigates the selective recovery of REEs via sulfation roasting and water leaching. Systematic experiments were conducted on crushed and demagnetized NdFeB magnet powders, with roasting performed under varying SO₂/O₂ atmospheres, gas flow rates, and temperatures (500–800 °C). At high roasting temperatures, suboptimal REE recovery is observed due to the formation of RE oxides. The Factsage phase diagram analysis predicted, and experiments confirmed, that selective REE sulfation is favoured between 600 and 700 °C, while higher temperatures promote oxide formation and lower temperatures favour non-selective sulfation. SEM–EDS analyses demonstrated the formation of REE-sulfate-rich rims and iron oxide cores at optimal conditions. Water leaching at room temperature yielded an increase in REE extraction efficiency with minimal iron dissolution at 700 ℃ compared to that at 600 or 800 ℃. The integrated approach presented here establishes a robust framework for advancing sustainable REE recovery technologies.

   6. Influence of Roasting Temperature on Phosphorus Transformation and Leaching Behavior During Sulfuric Acid Roasting of Montebrasite Ore: Thermodynamic and Experimental Insights

      Abdulmalik Hamza Bichi, Rongbo Zhu, Yuanjian Liu, Pengfei Zhao, Shenghai Yang, Yongming Chen

      Abstract

      This study investigates the influence of roasting temperature on phosphorus transformation and leaching behavior during sulfuric acid roasting of Montebrasite ore with formula LiAlPO₄(OH)_0.62F_0.38. Montebrasite poses a persistent challenge due to the strong coupling between phosphorus (P) and aluminum (Al), which complicates selective recovery during conventional processing. Sulfuric acid (H₂SO₄) roasting experiments were performed across a temperature range of 140–900 °C with a fixed acid dosage of 50% ore mass, followed by water leaching at 80 °C. Thermodynamic modeling (100–200 °C, 0.5 and 2.0 mol H₂SO₄ dosage) was employed to predict phase stability and transformation pathways, while experimental validation was carried out using ICP-OES, and X-ray Diffraction (XRD) analyses. The results reveal a temperature-dependent shift in phosphorus speciation, at low roasting temperatures (<300 °C), P is predominantly released as soluble H₃PO₄, enhancing its leachability but accompanied by significant co-dissolution of Al. Above 600 °C, however, P reacts with Al-bearing species to form insoluble AlPO₄, resulting in sharp suppression of P extraction (<0.5% at 800 °C). In contrast, lithium (Li) is stabilized as soluble Li₂SO₄ above 700 °C, maintaining high extraction efficiency (>93%). These findings highlight the dual role of roasting temperature: low temperatures favor P solubilization but reduce selectivity, while high temperatures suppress P extraction yet enable nearly selective lithium recovery. The study provides a mechanistic understanding of phosphorus-aluminum coupling during sulfuric acid roasting and offers critical insights for designing optimized processing strategies to balance selective Li recovery with efficient P separation in Montebrasite ore.

   7. Recovery of Lithium from Battery Recycling Wastewater Using Electrodialysis

      Kurniawan Kurniawan, Mason Wasilk, Jessica Macholz

      Abstract

      Bipolar-assisted electrodialysis (BPED) is a membrane-based separation technique widely used for treating wastewater. One of its major advantages is the ability to produce three valuable products: a base, an acid, and desalinated water. This study explores the use of BPED to treat wastewater generated during battery recycling, which contains lithium and complex chemical compositions. The efficiency of lithium recovery is a key metric of the process. Various parameters, including the initial concentration of acid and base compartments, stack voltage, volume ratio, and processing time, were examined and optimized. The purity of the recovered lithium product, lithium hydroxide (LiOH), was evaluated to meet battery-grade standards.

   8. Recycling of Dried Chargeable Batteries to Recover Critical Metals (Li, Co, Ni, Mn) for Circular Economy

      Rukshana Parween, Ankur Sharma, Karina Rani, Balram Ambade, Manis Kumar Jha

      Abstract

      India's growing emphasis on clean energy and electric mobility has significantly increased the demand for critical metals such as lithium (Li), cobalt (Co), nickel (Ni), and manganese (Mn) as essential materials/metals for the manufacturing of lithium-ion batteries (LIBs). Present paper reports a developed process flowsheet for the recovery of Li, Co, Ni, Mn, etc., metals from dried chargeable batteries. This involves safe pretreatment process of dried chargeable batteries, comprising discharging, crushing, and physical beneficiation (wet or dry process) to liberate black mass. This black mass is leached using suitable lixiviant to get metals in solution. Precipitation or electro winning are used to recover the end products after the leach solution is processed to get pure solution metals using advanced separation processes like solvent extraction (SX) or ion exchange (IX). The end products are metals or salts of Li, Co, Ni, and Mn that are adequately pure.

   9. Recycling of LiFePO4 Batteries via Solar-Aluminothermic Reduction: Towards a Sustainable Practice of Pyrometallurgical-Based Recycling

      Bintang A. Nuraeni, Deddy C. Nababan, M. Akbar Rhamdhani

      Abstract

      The growing demand for Li-ion batteries across industries has significantly increased electronic waste, highlighting the urgent need for sustainable recycling methods. LiFePO₄ (LFP) is emerging as one of the most rapidly advancing cathode chemistries, with recent projections suggesting that LFP's market share will continue to grow in the next decade. Recycling Li-ion battery cathode materials using aluminum waste, such as current collectors, aluminum swarf, and aluminum dross, through aluminothermic reduction offers a resource-efficient process that eliminates the need for energy-intensive reductants. This study investigates the thermodynamics and experimental validation of aluminothermic reduction of LFP at various temperatures and atmospheres using a solar-simulator furnace. The proposed approach seeks to address the limitations of the pyrometallurgical battery recycling process by developing a recycling method that utilises secondary-resource reductants and renewable heat source. The information and data obtained are useful in determining the optimised parameters of recycling end-of-life LFP batteries via the pyrometallurgical route.

   10. Development of the Potential Lithium Industry in the United States

       Khosrow Biglarbigi, Marshall Carolus, Vanessa Murakami

       Abstract

       In response to widespread electrification, the U.S. and global demands for lithium are expected to grow significantly over the next decades. While U.S. production is currently limited to Nevada, there are several projects under consideration throughout the U.S. INTEK has recently completed an assessment of the domestic lithium production potential. This assessment included: (1) potential sites for hard rock mining, solution mining, and direct lithium extraction (DLE) applied to brine from aquifers and produced oil and gas waters, (2) five existing and emerging extraction and processing technologies, (3) detailed project-level economic analysis, and (4) estimation of regional and national results including production, reserves, and socio-economic benefits under a range of technology and economic assumptions. The analysis determined that the lithium resources have the potential, under certain economic and technology scenarios, to meet the projected demand in the U.S. and support an export market. To realize this potential, concerted efforts are required between private industry, local, state, and federal governments to address challenges associated with resource access, technology development, permitting, and market.

   11. Lithium Metal Battery Anode Production via Room Temperature Electrolysis

       Michael J. Dziekan, Kelly E. Cohen, Matthew Earlam, John N. Hryn

       Abstract

       Lithium metal anode batteries have emerged as a focus of considerable research interest and are projected to raise global lithium metal demand to over five million tons by 2050, whereas current annual production is limited to approximately 2,000 metric tons. Scaling with current methods is difficult because the prevailing industrial route uses high temperature electrolysis of molten lithium chloride, which consumes substantial energy and generates chlorine gas that must be contained or neutralized. Argonne National Laboratory has patented a room temperature electrowinning process that addresses these limitations by producing lithium metal while releasing oxygen as a byproduct, eliminating chlorine formation and reducing environmental and safety burdens. A key attribute is feedstock flexibility as the process can accept treated domestic spodumene and processed brines derived from lithium chloride, allowing producers to switch between ore and brine sources as markets evolve which strengthens supply chains and aligns production with regional resources. This approach integrates a purpose designed ion conducting membrane with tailored electrolyte chemistry and controlled current density. These elements promote smooth lithium deposition and suppress dendrite growth. The resulting metal is dense and uniform, suitable for battery applications which require high purity metal. Room temperature operation lowers energy input and avoids hazardous chlorine management. Together, these attributes can reduce operating costs, shrink the environmental permits required, and enable modular deployment to meet rapidly rising global demand.

4. Rare and Critical Minerals Processing

   1. Frontmatter

   2. A Novel Process for Recovery of Rhenium from Superalloy Material

      Morgan M. Simco, Richard C. Bradshaw, Robert W. Hyers

      Abstract

      Rhenium, a rare and high value element, is added in considerable amounts to nickel-based superalloy compositions due to its ability to enhance creep performance. Besides the economic incentives, the limited availability of rhenium, along with the growing demand for superalloys, raises concerns that demand may outpace supply. Reducing or eliminating rhenium from superalloy compositions is not a viable solution; therefore, work has gone into the development of effective recovery techniques. Superalloy scrap, with its high rhenium content, is a rich source of rhenium compared to primary ores, making it an attractive source for recovery. Various routes have been attempted to recover rhenium from superalloy scrap, including many routes that capitalize on the high volatility of rhenium oxide. However, the absence of a widely accepted industrial process to recover rhenium from superalloy material, highlights the need for improvement in this area. The initial development of a novel high temperature recycling approach to recover metallic rhenium from contaminated superalloy material will be presented. Preliminary tests of this process show no loss of rhenium or any other high value elements during melting, supporting its continued development.

   3. Alkaline Leaching of Uranium from an Indigenous Boltwoodite Ore for Nuclear Fuel Production

      Alafara A. Baba, Mustapha A. Raji, Rafiu B. Bale, Kuranga I. Ayinla, Fausat T. Akanji, Daud T. Olaoluwa, Christianah O. Adeyemi, Ayo F. Balogun

      Abstract

      As global energy demand increases appreciably due to rising population growth and the expansion of manufacturing industries, nuclear energy will play a vital role in meeting future demand, thanks to its high energy density and low carbon emissions. Thus, uranium is a crucial nuclear fuel and a vital strategic resource for national security. The separation and recovery of uranium from an indigenous boltwoodite ore in ammonium hydroxide (NH₄OH) leaching was examined. The influences of some experimental parameters, including leachant concentration, reaction temperature, and particle size, were studied to optimize the leaching kinetics. At a set of established conditions, uranium dissolution reached 76.1%, as the activation energy of 22.27 kJ/mol was estimated for the diffusion-controlled leaching process. The purification of the uranium leach liquor was subsequently achieved through precipitation routes to obtain high-grade industrial uranium compound recommended for use in nuclear fuel applications.

   4. An Integrated Strategy and Process for Recovery of Germanium from Metallurgical By-Products and Waste Streams

      Caden Ingraham, Jerome Downey, Grant Wallace

      Abstract

      Germanium is a strategic material essential for electronics, optics, and solar cell applications. The U.S. relies on imports to satisfy over half of its germanium demand; domestic extraction of germanium would reduce market volatility and support independent growth. Germanium does not commonly form ores in mineable quantities but can become enriched in metallurgical waste streams. The present study involves a multi-staged hydro- and pyrometallurgical process for the recovery of germanium from metallurgical wastes. Chlorination and volatilization present a simple and effective pretreatment method of concentrating germanium in an aqueous solution. Following pretreatment, germanium is adsorbed onto magnetite particles, which are then magnetically separated from solution with high efficiency. Adsorption kinetics have been modeled, and competitive adsorption experiments with a common gangue element have been completed. Chlorination experiments involving the volatilization of germanium tetrachloride from a synthetic charge as well as a fumed slag sample have been completed. The influence of various surface functionalization’s on magnetite’s germanium uptake has been investigated. Additional work quantifying the selectivity of magnetite particles for germanium in multicomponent solutions is ongoing, with the goal of optimizing the final purification step.

   5. Study on Electrochemical Selenium Extraction by Voltammetry on a Glassy Carbon Electrode

      Xueshuang Gong, Shasha He, Yichao Yang, Guozheng Zha, Wenlong Jiang

      Abstract

      Cyclic Voltammetry (CV) was employed to systematically investigate the electrochemical deposition and stripping behavior of selenium dioxide (SeO₂) in a nitric acid medium on a Glassy Carbon Electrode (GCE), aiming to reveal the reaction mechanism of low-cost electrode materials for selenium recovery. A three-electrode system was adopted in the experiment, with GCE as the working electrode, a graphite rod as the counter electrode, and an Ag/AgCl electrode as the reference electrode. Tests were conducted in an electrolyte containing 0.1 M SeO₂ and 0.1 M HNO₃ at scan rates ranging from 2 to 100 mV/s. Results from the scan rate experiment showed that the peak currents of C2 and C3 exhibited a linear relationship with the square root of the scan rate, indicating that the deposition process is diffusion-controlled and self-limiting. This study provides a key theoretical basis for the parameter optimization of low-cost electrochemical selenium extraction technology.

   6. Hydrometallurgical Processing of Discarded PCBs to Recover Precious and Base Metals

      Shushant Shekher Rakshit, Rekha Panda, Ankur Sharma, Apurva Aditi, Manis Kumar Jha

      Abstract

      A novel hydrometallurgical process flowsheet for recovering precious and base metals from printed circuit boards (PCBs) begins with depopulation of components like heat sinks (for aluminum recovery), RAM/ICs (for gold), and other refurbishable items. RAM and ICs are treated with suitable lixiviant to dissolve gold, which is recovered via charcoal adsorption and high-temperature burning. Naked PCBs along with gold depleted RAMs and ICs undergo crushing and pulverization followed by two stage leaching using 20% H₂SO₄ and 10% H₂O₂ to dissolve copper, nickel and zinc. Sequential solvent extraction at pH 2.5 and 4.5 recovers copper and nickel respectively as copper sulfate and nickel sulfate salt solutions, while zinc is precipitated as Zn(OH)₂. The solid leached residue containing silver, lead, and tin were subjected for further treatments. This integrated route ensures selective and efficient metal recovery from electronic waste.

   7. Hydrometallurgical Extraction of Rare and Critical Metals (In and Sn) from Discarded Display Devices

      Karina Rani, Rekha Panda, Ankur Sharma, Apurva Aditi, Balram Ambade, Manis Kumar Jha

      Abstract

      The growing use of electronic devices has intensified the challenge of managing electronic waste (e-waste) while depleting critical resources such as indium (In) and tin (Sn). These strategic metals, primarily used as indium tin oxide (ITO) in flat-panel displays, are scarce and essential for high-tech industries. Typical analysis indicates that liquid crystal display (LCD) panels contain 0.01–0.02% In & 0.04–0.08% Sn. Apart from In and Sn the impurities are 0.05–0.08% Al and 1.95–2.31% Fe. The methodology involves safe dismantling, mechanical shredding for size reduction, and subsequent hydrometallurgical extraction. Indium leaching was optimized using dilute H₂SO₄ at elevated temperature with a suitable pulp density, achieving ~ 98% recovery. This study presents a sustainable, scalable process for recovering In and Sn from discarded LCD panels which will reduce e-waste impact and promote circular economy by reintroducing critical metals into the production loop, thereby reducing dependency on primary resources and enhancing sustainability.

   8. Secondary Production of Tantalum from Additive Manufacturing Swarf

      Sarah M. Fenton, Richard Bradshaw, Gwendolyn P. Bracker, Robert W. Hyers

      Abstract

      Tantalum is a material of growing interest in the field of additive manufacturing for its high corrosion resistance, ductility, thermal and electrical conductivity, and chemical resistance in acidic environments and at elevated temperatures. Solid-state processes have been increasingly explored due to its high melting point as a refractory metal, and cold spray is of particular interest as tantalum powder has been shown to have a deposition efficiency of 50–100%. The USGS and the EU consider tantalum to be a critical mineral, but the supply chain can be stabilized by expanding and strengthening secondary production. Machining cold spray parts generates swarf, grindings, and other waste that contain a significant amount of tantalum, which can act as a resource for tantalum recovery. This work will analyze current recycling processes of tantalum, and the possible routes that can be explored to recover tantalum from additive manufacturing waste.

   9. A Review on the Recovery of Tantalum Oxide from Tantalum Capacitors of Printed Circuit Boards

      Subrat Shekhar, Rekha Panda, Rukshana Parween, Ankur Sharma, Balram Ambade, Manis Kumar Jha

      Abstract

      Tantalum oxide (Ta₂O₅), used in solid-state capacitors of printed circuit boards (PCBs), is a critical metal essential for miniaturized electronics. Due to limited global reserves and geopolitical risks, recycling tantalum from electronic waste is gaining importance. This review explores current and emerging techniques for recovering tantalum oxide from scrap tantalum capacitors.Pyrometallurgical methods like plasma and chlorination offer high-purity outputs but are energy-intensive. Hydrometallurgical approaches, especially those using hydrofluoric acid, provide excellent selectivity but pose environmental hazards. To address these issues, integrated pyro-hydrometallurgical flowsheets are gaining attention. Processes such as pyrolysis followed by acid leaching or chlorination have demonstrated high efficiency and reduced environmental impact. The review also highlights innovative methods like microwave-assisted reduction and zeolite-based purification as future pathways. Overall, the paper emphasizes that a combination of advanced processing technologies and improved e-waste sorting systems is key to achieving sustainable tantalum recovery from discarded electronics.

5. Poster Session

   1. Frontmatter

   2. Comparative Study of Organic and Inorganic Leaching Agents for Lithium Recovery from Lepidolite and Spodumene

      J. Martínez Soto, J. Juárez Tapia, F. Patiño Cardona, M. Reyes Pérez, M. Flores Guerrero, R. Vázquez García, V. Acosta Sánchez, G. Cisneros Flores, A. Hernández Martínez

      Abstract

      This study evaluated the characterization and comparative leaching of lithium from pegmatitic minerals lepidolite and spodumene. Structural analyses by X-ray diffraction (XRD) confirmed lepidolite as the primary lithium-bearing phase, associated with muscovite and andradite, while spodumene was identified along with traces of B₂O₃ and MgO. Digital morphological and elemental analyses corroborated these identifications, revealing lamellar surfaces in lepidolite and granular to prismatic crystals in spodumene. Leaching experiments were conducted under controlled laboratory conditions (30 °C, 800 rpm, 37 µm, pulp density 1 g·L⁻¹), employing mineral acids, organic acids, amino acids, and salts. In lepidolite, sulfuric acid achieved lithium recoveries above 80%, followed by oxalic acid (~70%), confirming the effectiveness of acidic media in disrupting its silicate framework. In contrast, α-spodumene exhibited limited reactivity, with maximum recoveries of ~ 30% under malic acid, underscoring the need for prior activation stages (thermal conversion or alternative treatments). The results highlight the decisive influence of mineralogy and leaching agents on lithium extraction efficiency, emphasizing that lepidolite is more amenable to direct hydrometallurgical processing, whereas spodumene requires innovative strategies to enable its industrial utilization.

   3. Comparison of Magnetite Adsorbents for Use in the Separation of Rare Earth Elements from Aqueous Solution

      Robert F. West, Jerome P. Downey, Grant C. Wallace, Teagan Leitzke

      Abstract

      Rare earth elements (REEs) are essential to advanced technologies, yet their separation and recovery remain costly and inefficient. This study evaluated REE adsorption from aqueous solution using unfunctionalized magnetite (Fe₃O₄) and surface-functionalized variants with amine (Fe₃O₄-NH₂) and carboxylic acid (Fe₃O₄-COOH) groups. Single-element tests showed rapid uptake, with >99% removal within minutes. Kinetic modeling of unfunctionalized Fe₃O₄ fit the pseudo-second-order model (R² > 0.99), indicating chemisorption controlled by surface-site availability. Concentration and dosage studies confirmed the importance of the adsorbent-to-adsorbate ratio, as lower REE levels and higher particle loadings improved removal, while multi-element systems showed reduced efficiencies from competitive adsorption. Lanthanum exhibited lower uptake at high concentrations, particularly with functionalized particles, suggesting potential for selective separation. Results demonstrate that unfunctionalized Fe₃O₄ enables efficient bulk REE removal, while functionalization offers opportunities to tailor selectivity. These findings highlight the potential of continuous flow material recovery systems to handle variable-composition feedstocks, such as ore leachates and recycled materials, supporting scalable, solvent-free REE separation for industrial recovery processes.

   4. Leaching Kinetics with Modelling for the Dissolution of Ni, Sn, and Fe from Scrap Alloy

      Ankur Sharma, Karina Rani, Subrat Shekhar, Manis Kumar Jha

      Abstract

      Recovery of critical metals such as nickel (Ni), tin (Sn), and iron (Fe) from secondary resources is essential due to metal scarcity and environmental concerns. Present studies explore leaching behaviour and kinetic modelling of Ni–Sn–Fe alloy powders (Ni: 25–30%, Sn: 12–17%, Fe: 5–10%) generated as industrial waste. Leaching studies were made varying experimental parameters, i.e. concentration of acid, volume of oxidant, pulp density, agitation speed, time, and temperature. Metal dissolution of ~99.99% was achieved using 20–25% HCl (v/v) and 10% H₂O₂ (v/v) at 75–100 °C for 2–3 h, with 100 g/L pulp density and 400 rpm agitation. Recovered metals were obtained as sheets, salts, and powders using electrowinning and precipitation techniques, respectively. Kinetics of the leaching was fitted well with proven model and validated with SEM–EDS results. The results of the studies will be useful for process development after scale-up and pilot trials.

   5. Electrochemical Co-deposition of Neodymium and Cobalt in Urea and Choline Chloride Ionic Liquids

      Rajyashree Lenka, Ramana G. Reddy

      Abstract

      In this study, neodymium (Nd) and cobalt (Co) co-deposition was conducted in urea-choline chloride ionic liquid containing 0.038 M cobalt chloride and 0.029 M neodymium chloride. Electrodeposition was conducted at a temperature of 373 K under an applied potential of −3.5 V. The current density of 111 A/m² was obtained. The X-ray diffraction analysis confirmed the formation of the Nd-Co deposit on the cathode surface. The morphology and elemental composition were examined using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). SEM images suggested a uniform Co-Nd deposit with a coarse-grained structure, and EDS analysis showed the presence of Nd and Co. The results demonstrate a successful co-deposition of Co-Nd in urea-ChCl ionic liquids.

6. Backmatter