Rare Earth Supply Research Articles

Quantification and recovery prospects of critical metals and rare earth elements in Victorian brown coal fly ash: A promising secondary source for critical metal extraction

Coal fly ash (CFA), an anthropogenic waste generated from the combustion of coal, is in research focus for the potential it holds in extracting critical metals. Within the classification of critical metals, includes a group of 16 commercially significant metals known as rare earth elements (REEs). The supply of REEs is touted as one of the building blocks of the 21st century to realize a sustainable future. High demand projections for the future coupled with market monopolization, provide an impetus to extract REEs from secondary resources such as CFA. In this study, three Victorian brown CFA samples were examined, quantifying 41 metals and 16 REEs. All three CFA samples had an outlook coefficient (i.e., ratio of the relative amount of critical REE to the relative amount of excess REE) > 0.7, with an observed light REE enrichment and Eu anomaly, implicating the samples as a suitable feedstock for REE extraction. Quantification studies rendered Loy Yang CFA, from the largest power station in Australia, to be rich with REEs with a total metal concentration of 418 mg/kg, followed by CFA from other power stations (Yallourn: 73.6 mg/kg and Morwell: 36.1 mg/kg). A comparative study for different methods of calibration during inductively coupled plasma - mass spectrometry analysis (and external vs internal calibration), depicted the reproducible nature of results while using an internal standard. Subsequently an in-house developed multi-element standard addition method is proposed, within an accuracy of 2–50 %. A new sequential extraction method for studying modes of occurrences in CFA, depicting REE association with larger fractionation, is explored, with results rendering REE association with: aluminosilicate bound (~ 61.2 %) > acid soluble fraction (23.1 %) > crystalline Fe bound (5.9 %) > organic matter bound (5.3 %) > amorphous Fe bound (3.5 % TREE) > Mn-oxide bound (0.9 % TREE) > water soluble mineral bound (0.1 % TREE). This underpins the strong REE association in the residual and acid soluble fraction in brown CFA.

Advancements in functional adsorbents for sustainable recovery of rare earth elements from wastewater: A comprehensive review of performance, mechanisms, and applications.

Rare earth elements (REEs) are crucial metallic resources that play an essential role in national economies and industrial production. The reclaimation of REEs from wastewater stands as a significant supplementary strategy to bolster the REEs supply. Adsorption techniques are widely recognized as environmentally friendly and sustainable methods for the separation of REEs from wastewater. Despite the growing interest in adsorption-based REEs separation, comprehensive reviews of both traditional and novel adsorbents toward REEs recovery remain limited. This review aims to provide a thorough analysis of various adsorbents for the recovery of REEs. The types of adsorbents examined include activated carbons, functionalized silica nanoparticles, and microbial synthetic adsorbents, with a detailed evaluation of their adsorption capacities, selectivity, and regeneration potential. This study focuses on the mechanisms of REEs adsorption, including electrostatic interactions, ion exchange, surface complexation, and surface precipitation, highlighting how surface modifications can enhance REEs recovery efficiency. Future efforts in designing high-performance adsorbents should prioritize the optimization of the density of functional groups to enhance both selectivity and adsorption capacity, while also maintaining a balance between overall capacity, cost, and reusability. The incorporation of covalently bonded functional groups onto mechanically robust adsorbents can significantly strengthen chemical interactions with REEs and improve the structural stability of the adsorbents during reuse. Additionally, the development of materials with high specific surface areas and well-defined porous structures is benifitial to facilitating mass transfer of REEs and maximizing adsorption efficiency. Ultimately, the advancement of the design of efficient, highly selective and recyclable adsorbents is critical for addressing the growing demand for REEs across diverse industrial applications.

Recent progress in electrochemical recycling of waste NdFeB magnets.

Neodymium iron boron (NdFeB) magnets are critical components in green energy technologies and have received increasing attention due to the limited availability of the raw materials, specifically rare earth elements (REEs). The supply risks associated with primary mining of RE ores, which have significant environmental impacts, underscore the necessity for recycling RE secondary resources. Waste NdFeB magnets, generated during manufacturing processes and recovered from end-of-life products, represent valuable RE secondary resources. Recycling these materials can ensure a reliable and sustainable supply of REEs. Compared to conventional metallurgical processes, electrochemical strategies offer advantages such as high efficiency, selectivity, ease of operation, and environmental friendliness. This review presents an overview of the current status and future prospects of electrochemical technologies for recovering RE metals, alloys, or compounds from waste NdFeB magnets. Special emphasis is placed on molten salt electrolysis and room-temperature electrolysis, including detailed reaction mechanisms involved in the recycling processes. Additionally, challenges and future strategies for the electrochemical recycling of waste NdFeB magnets, focusing on environmental impact evaluation, efficient recovery, and reduced reagent consumption are proposed.

Rare earth element (REE) speciation in municipal solid waste incineration ash

A robust and sustainable supply of rare earth elements (REE) is critically needed for clean-energy technologies, which has stimulated substantial interests in REE recovery from waste streams. Municipal solid waste incineration ash (MSWIA) was recently recognized as a potentially important REE resource, yet REE speciation in MSWIA remains poorly understood. This study employed synchrotron X-ray spectroscopy and microscopy techniques to elucidate the speciation of representative REE (Y, Ce, and Nd) in different MSWIA samples. Linear combination fitting of bulk X-ray absorption near edge structure (XANES) data indicated that Y-bearing Al/Fe oxides and phosphates are the primary Y-hosting phases. Micro-XANES of individual Y-containing particles identified by micro X-ray fluorescence (μXRF) mapping revealed notably different Y speciation at micro-scale from the bulk, consistent with the highly heterogeneous nature of MSWIA samples. The main REE-bearing phases in different size-fractionated MSWIA are similar: Y and Nd as oxides and xenotime/monazite, and Ce as apatite and monazite. Our results provide important insights for designing pre-screening processes (e.g., density separation) and optimizing extraction methods (e.g., pH, use of ligands) for cost-effective REE recovery from MSWIA.

Interplay of Chinese rare earth elements supply and European clean energy transition: A geopolitical context analysis

The European clean energy sector sources approximately 98 % of its rare earth materials from China. We examine Chinese rare earth supply's effect on European renewable energy, particularly solar and wind sectors from 1990 to 2020. Using the gravity model, we find a positive correlation between China's rare earth supply and European solar energy during bullish markets. A similar response is seen in wind energy during bearish markets, considering global and China-specific geopolitical risks. We also observe a negative correlation between China's economic growth and mineral supply to Europe, with European income growth having no significant impact. Additionally, multiplicative economic growth negatively impacts Chinese mineral supply. The study also reveals a positive link between oil prices, rare earth export prices, geopolitical risks, and China's mineral exports. Distance negatively affects supply dynamics in the wind model but not in the solar model. However, the originality of this study lies in its examination of China's role as a rare earth supplier for Europe's clean energy transition, integrated into a gravity model. Significantly, this research provides potential trade insights and formulates an economic policy implication framework to guarantee a steady supply of China's rare earths for Europe's green deal objectives, while addressing the associated geopolitical risks.

In-Situ X-ray Diffraction/Fluorescence Analysis of Dy–Cu Electrochemical Alloying and Dealloying in Molten LiCl–KCl–DyCl3

1. Introduction Recycling spent Nd magnets is important for guaranteeing a stable rare earth (RE) supply in Japan. As a new recycling process of Nd magnets, the authors have studied a one-step method using molten salt and alloy diaphragms [1-3], where Dy or Nd is selectively permeated by controlling the potential of the alloy diaphragms. This technique is based on the rapid electrochemical formation of RE–iron group (IG) alloys in molten salts. To investigate the mechanism of the rapid alloy formation, the authors recently conducted in situ energy-dispersive X-ray diffraction measurement for the electrochemical alloying and de-alloying of Dy–Ni in molten LiCl–KCl [4,5]. Through these results, new insights into Dy–Ni alloying and de-alloying were obtained. However, the reason why the electrochemical formation of RE–IG alloys proceed so rapidly is still unclear. Therefore, we investigated the mechanism by comparing Ni with the other metal, Cu, which has a similar crystal structure (fcc) to Ni, and its alloy formation rate with RE is relatively high [6]. In this study, in situ X-ray fluorescence (XRF) measurement of Dy–Cu alloying and de-alloying in molten LiCl–KCl was performed and the alloying/de-alloying behaviors of Dy–Cu and Dy–Ni were compared. 2. Experimental The experiments were conducted in a similar manner to the previous studies [4,5] at the BL28B2 beamline of SPring-8. 35.0 g of LiCl–KCl (44 : 56 wt% eutectic composition, 35.0 g) was set in a graphite crucible inside a glovebox with an Ar atmosphere. Pre-electrolysis was conducted before the experiment. An electric furnace with windows was fixed on the transition stage. Electrolysis was conducted in Pyrex vessel at 723 K in a dry Ar atmosphere. After potential calibration by the Li+/Li equilibrium potential using a Mo electrode, DyCl3 was added to the melt up to 0.5 mol%. A Cu plate (5 mm × 15 mm × 0.1 mmt), an Ag+/Ag, and the graphite crucible were used as the working, reference, and counter electrodes, respectively. After the measurement of cyclic voltammetry, the potentiostatic electrolysis was conducted using the same Cu plate for 180 min at 0.5 V vs. Li+/Li and then, potential was shifted to 1.5 V vs. Li+/Li and kept for 30 min. XRF measurements were started simultaneously with electrolysis. The incident beam size was 0.1 mm × 2.0 mm and irradiated to the Cu plate in the molten salt. The take-off angle was set at 5°. Transmitted X-rays were consecutively detected with the integration time of 120 s. 3. Results and Discussion The X-ray fluorescence peaks of Dy Kα1, Kα2, and Kβ1 were confirmed. Fig 1 shows peak area–time data for X-ray fluorescence of Dy Kα1 during Dy–Cu alloying and de-alloying. The peak area increased as the alloying progressed, which seemed to correspond to the formation and growth of Dy–Cu alloy layer. The peak area slightly decreased during de-alloying. Compared to Dy–Ni alloying/de-alloying [5,6], the intensities of fluorescence peaks were weak. These results suggest that the was alloy formation rate is smaller in the case of Cu than that of Ni. Acknowledgement This work was partly supported by the New Energy and Industrial Technology Development Organization (NEDO) of Japan. Synchrotron radiation studies were performed at the BL28B2 beamline of SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI, Proposal No. 2022B1338).

Polymer-Based Extracting Materials in the Green Recycling of Rare Earth Elements: A Review.

Rare earth elements (REEs) are becoming increasingly important in the development of modern and green energy technologies with the demand for REEs predicted to grow in the foreseeable future. The importance of REEs lies in their unique physiochemical properties, which cannot be reproduced using other elements. REEs are sourced through mining, with global exploration of additional commercially viable mining sites still ongoing. However, there is a growing need for recycling of REEs due to the current supply of REEs not matching the growing demand, the environmental impact of REE mining and processing (the so-called "balance problem"), and the generation of large volumes of harmful electronic waste (e-waste). Industrial REE processing is mainly carried out by hydrometallurgy processes, particularly solvent extraction (SX) and ion exchange (IX) technologies. However, these methods have a significant environmental impact due to their intensive use of harmful and nonsustainable reagents. This Review highlights the development of approaches involving polymer-based extracting materials for REE manufacturing as more sustainable alternatives to current industrial REE processing methods. These materials include supported liquid membranes (SLMs), solvent impregnated resins (SIRs), macro and micro capsules, polymer inclusion membranes (PIMs), and micro polymer inclusion beads (μPIBs). Polymer-based extracting materials have the advantage of more economical regent usage while applying the same extractants used in commercial SX, enabling applications analogous to the current industrial process. These materials can be fabricated by a variety of methods in a diverse range of physical formats, with the advantages and disadvantages of each material type described and discussed in this Review along with their applications to REE processing, including e-waste recycling and mineral processing.

Scalable and facile fabrication of sulfonic-acid-functionalized porous hypercrosslinked polymers for efficient recovery of rare earth elements from tailing wastewater

The separation and enrichment of rare earth elements (REEs) from tailing wastewater is of great significance for the sustainable supply of REEs and environmental remediation. As Al3+ exhibits extreme similar properties with REE3+, selective recovery of REE3+ from the sulphate tailing wastewater remains a considerable challenge. Based on the difference in the binding stability of REE3+ and Al3+ with sulfate ions, the utilization of sulfonic acid groups may provide a promising method for enhancing the selectivity of REE3+/Al3+ in the sulphate aqueous solution. Herein, a series of sulfonic-acid-functionalized hyper-crosslinked polymers (SHCP-Ps) were successfully synthesized through a facile, scalable and one-step method catalyzed by chlorosulfonic acid, which has the advantages of high sulfonic acid density (3.27 mmol/g), specific surface area (1044.6 m2/g), abundant micropores and superhydrophilicity. These properties result in SHCP-P exhibiting fast adsorption kinetics (30 min) and high adsorption capacities (106.78 mg/g (La), 111.99 mg/g (Eu) and 126.27 mg/g (Lu)). Additionally, it exhibits extremely high REE3+/Al3+ selectivity (SF(La/Al) = 6929, SF(Eu/Al) = 4810, SF(Lu/Al) = 3003) in sulfate medium, surpassing that of most existing REEs adsorbents. Upon application of SHCP-P to actual wastewater, the recovery rate of total REE3+ was observed to reach 87 %, while the adsorption rate of Al3+ was found to be 0. Simultaneously, SHCP-P exhibits both high reusability and magnification synthesis capabilities. The results indicate that SHCP-P has significant potential for industrial applications in the selective recovery of REEs from tailing wastewater.

The Use of Fuzzy Modelling Based on Expert Knowledge to Determine Poland’s Energy Security Index Taking into Account Political Conditions

This article presents the results of research on the energy security index in Poland. Since the development of renewable energy sources forced by the transformation of the national energy system will require an increased supply of rare earth elements, the level of demand for these metals was taken into account when determining the energy security index. Furthermore, the development of renewable energy sources in Poland will directly depend on the volume of energy demand and, as the events of previous years have shown, on political and legal conditions, especially in the case of wind energy. Since some of these factors are qualitative, it was impossible to use a quantitative method. Therefore, fuzzy sets were used. Fuzzy modelling is based on expert knowledge. Using this method, the authors created three alternative scenarios for the development of Poland’s energy security index: pessimistic, optimistic, and the most probable.

Characterization of Rare Earth Elements in Cassiterite-Associated Minerals in Bangka-Belitung Islands, Indonesia

Rare earth elements (REEs) are crucial to numerous industries of high-technology as raw materials. The growth of a long-term relationship between REE supply and demand to develop hi-tech industries is becoming tight in the world market, while the mineral supply chain is being distorted by COVID-19. The availability of information and data regarding the REE resource potential and characteristics are interesting research subjects to examine its economic value as alternative sources. This research aims to provide basic information about the existence and characteristics of REEs in cassiterite-associated minerals located in Bangka and Belitung Islands. Fifty-one samples consisting of primary deposits, placer deposits, concentrates, and tailings were collected from the southern Bangka and Belitung region. The samples were analyzed using microscope, x-ray diffraction (XRD), scanning electron microscopy (SEM), electron probe micro-analysis (EPMA), and inductively coupled plasma mass spectrometry (ICP-MS). The results show that the REE-bearing minerals comprised monazite and xenotime. Monazite, the most dominant REE-bearing mineral, contains light REEs (Ce-dominant), while xenotime contains heavy REE (Y-dominant). The results of SEM with energy-dispersive spectroscopy show that monazite contains other LREE (La and Nd), and xenotime also contains other HREE (Dy and Yb). Moreover, zircon and ilmenite can be considered as economical cassiterite-associated minerals that have other mineral inclusion, but have no REE contain.

Forecasting synergistic pathways between rare earth elements, renewable energy, and product and economic complexities in achieving a low-carbon future

Recent decades have witnessed an unprecedented transformation in the global energy landscape, driven by environmental concerns and the quest for sustainable economic growth. As the world grapples with the urgent need for decarbonization, the utilization of renewable energy technologies with the instrumental role of rare earth elements (REEs) has come to the forefront. However, empirical investigations into their synergistic pathways for product and economic complexities concerning achieving a low-carbon future remain scarce. Therefore, we forecast synergistic pathways between the REE supply, renewable energy, economic and product complexities, and GDP growth using a panel dataset of 11 REE-producing countries from 1990 to 2023. We used Common Correlated Effects and Temporal Causal Models as primary methods to estimate panel long-run elasticities and subsequently forecast mutual causal synergies between the variables. The results indicated that REE supply led to renewable energy and economic growth that further elevated the countries’ product and economic complexities rankings. GDP growth increased REE production, economic complexity, and renewable energy directly, and consequently, product complexity and REE production through them. This underscores the positive role of REE production coupled with renewable energy technologies in achieving a low-carbon future based on economic diversification, enhanced industrial capabilities, and technological sophistication.

Assessing China's rare earth supply security

As strategic minerals become increasingly critical in the competition among great powers, combined with high-quality development requests, their security issues gain more prominence. Based on an in-depth understanding of the connotation of China's strategic mineral security, this article developed a rare earth security assessment index system with 3 sub-objects: global supply stability, domestically economic security and coexistence, then conducted sensitivity analysis using Monte Carlo simulation. The results show that: (1) Global supply stability increased, then fluctuated and declined due to deficiencies in sustainable development and politics, affecting China's long-term rare earth security index; (2) Domestically economic security was weakening due to reduced mine supply, impacting China's short-term rare earth security index; (3) The coexistence index was rising, influenced by industry chain security changes, with increases benefiting China's rare earth security index; (4) China's rare earth security level rose from 2010 to 2022, tracking the coexistence index, indicating that international market integration boosts rare earth security. Based on the above findings, the article puts forward corresponding policy implications.

First-Principles Study of Ti-Doping Effects on Hard Magnetic Properties of RFe11Ti Magnets

Due to the rare earth supply shortage, ThMn12-type RFe12-based (R is the rare earth element) magnets with lean rare earth content are gaining more concern. Most ThMn12-type RFe12 structures are thermodynamically metastable and require doping of the stabilizing element Ti. However, the Ti-doping effects on the hard magnetic properties of RFe11Ti have not been thoroughly investigated. Herein, based on density functional theory calculations, we report the Ti-doping effects on the phase stability, intrinsic hard magnetic properties and electronic structures of RFe11Ti (R = La, Ce, Pr, Nd, Sm, Y, Zr). Our results indicate that Ti-doping not only increases their phase stability, but also enhances the magnetic hardness of ground-state RFe12 phases. Particularly, it leads to the transition of CeFe11Ti and PrFe11Ti from easy-plane to easy-axis anisotropy. Charge density distributions demonstrate that Ti-doping breaks the original symmetry of the R-site crystal field, which alters the magnetic anisotropy of RFe11Ti. Projected densities of states reveal that the addition of Ti results in the shift of occupied and unoccupied f-electron energy levels of rare earth elements, affecting their magnetic exchange. This study provides an insight into regulating the hard magnetic properties of RFe12-based magnets by Ti-doping.

Processability and Separability of Commercial Anti-Corrosion Coatings Produced by In Situ Hydrogen-Processing of Magnetic Scrap (HPMS) Recycling of NdFeB.

The recycling of NdFeB magnets is necessary to ensure a reliable and ethical supply of rare earth elements as critical raw materials. This has been recognized internationally, prompting the implementation of large-scale legislative measured aimed at its resolution; for example, an ambitious recycling quote has been established in the Critical Raw Materials Act Successful recycling in sufficient quantities is challenged by product designs that do not allow the extraction and recycling of these high-performance permanent magnets without excessive effort and cost. This is particularly true for smaller motors using NdFeB magnets. Therefore, methods of recycling such arrangements with little or no dismantling are being researched. They are tested for the hydrogen-processing of magnetic scrap (HPMS) method, a short-loop mechanical recycling process. As contamination of the recycled material with residues of anti-corrosion coatings, adhesives, etc., may lead to downcycling, the separability of such residues from bulk magnets and magnet powder is explored. It is found that the hydrogen permeability, expansion volume, and the chosen coating affect the viable preparation and separation methods as recyclability-relevant design features.

Ex-ante LCA of magnet recycling: Progressing towards sustainable industrial-scale technology

To alleviate the pressure on the rare earth supply chain, new technologies are under development for recovering, recycling and remanufacturing NdFeB magnets. In this study, the anticipated environmental performance of large-scale recycling is investigated and compared to the production of primary magnets. To do so, this ex-ante life cycle assessment combines input from measurements of pilot processes, expert technology forecasts, thermodynamic modeling, and equipment data from manufacturers. We examined the effect of four technology developments: process changes, size scaling, internal recycling, and optimization.The results show that at pilot scale, recovered NdFeB powders have lower impacts than primary powders for almost all impact categories. This demonstrates that the recovery of NdFeB alloys is environmentally beneficial. Magnets from anticipated large-scale recycling have over 80% lower impacts than primary magnets in most of the impact categories analyzed. All four investigated types of technology development contributed to this improved performance. The final configuration was validated by comparison with an industrial reference and theoretical optimum configuration. Four magnet manufacturing routes (sintering, extrusion, metal injection molding, bonding) have distinct environmental profiles, but all can progress to similarly low levels of impact. The choice among routes should be primarily based on the functional requirements.

Rare Earth and Resource Nationalism: What Happened Before and After China’s Embargo on Japan?

ABSTRACT The ban on the export of rare earth elements (REE) to Japan following the 2010 Senkaku boat collision is a salient case of economic sanctions. Chinese state media’s recent consideration of REE as a weapon in the trade war with the United States has brought China’s rare earth policy back into the limelight. This article discusses China’s REE policy from a theoretical perspective of resource nationalism. After examining how China adopted resource nationalism on REE before 2010, it continued to examine how Japan’s response to the ban on REE exports had an impact on China’s rare earth policy and thus, China’s rare earth resource nationalism has grown more thorough since 2010. On the one hand, Beijing has taken countermeasures against Tokyo’s bid to decrease its dependency on China’s REE supply and deter Beijing from placing export restrictions. On the other hand, lessons from its failure to control REE prices have led to the continuation and acceleration of China’s resource nationalism concerning its REEs.

Quantifying provincial in-use stocks of rare earth to identify urban mining potentials in the Chinese mainland

Recycling of rare earth elements (REE) can help to offset the increasing demand for REE minerals and enhance the diversification of the REE supply chain. The development of low-carbon technologies, such as new energy vehicles and wind turbines has expedited the accumulation of REE as “urban mines”. This trend offers prospects for the progress of REE recycling initiatives targeting end-of-life products. This study conducts a dynamic material flow analysis (combined top-down and bottom-up method) of nine products containing NdFeB permanent magnets (their scrap is regarded as the most important secondary resource of rare earth) in the Chinese mainland at a provincial level to identify end-of-life products and provinces with high urban mining potentials. Results indicate that e-bikes, wind turbines, and air conditioners have the most significant REE recycling potentials in the Chinese mainland. Provinces with large populations and robust economies, such as Guangdong and Jiangsu, exhibit greater potential for REE recycling. This study illustrates significant provincial disparities in the end-of-life recycling potentials of REEs in the Chinese mainland and highlights the significance of provincial-level assessments of urban mining potential in the planning of the REE recycling industry.

Critical material requirements and recycling opportunities for US wind and solar power generation

AbstractThe deployment of renewable energy generation technologies, driven primarily by concerns over catastrophic climate change, is expected to increase rapidly in the United States. Rapid increases in the deployment of wind and solar energy will translate to increases in critical material requirements, causing concern that demand could outstrip supply, leading to mineral price volatility and potentially slowing the energy transition. This study presents a detailed demand‐side model for wind and solar in the United States using dynamic material flow analysis to calculate the requirements for 15 elements: Cr, Zn, Ga, Se, Mo, Ag, Cd, In, Sn, Te, Pr, Nd, Tb, Dy, and Pb. Results show that transitioning to a completely decarbonized US energy system by 2050 could require a five‐to‐sevenfold increase in critical material flow‐into‐use compared with business as usual (BAU), with some materials requiring much larger increases. Rare earth elements (REEs) could require 60–300 times greater material flows into the US power sector in 2050 than in 2021, representing 13%–49% of the total global REE supply. Te requirements for reaching net zero by 2050 could exceed current supply, posing challenges for widespread deployment of cadmium‐telluride solar. We also investigate several strategies for reducing material requirements, including closed‐loop recycling, material intensity reduction, and changing market share of subtechnologies (e.g., using crystalline silicon solar panels instead of cadmium telluride). Although these strategies can significantly reduce critical material requirements by up to 40% on average, aggressive decarbonization will still require a substantial amount of critical material.

Chemical isolation of rare earth elements (as pure rare earth oxides) from Nd-Fe-B magnets and Ni-MH batteries

Rare earth elements (REEs) are increasingly in demand for their usage in electric vehicles, permanent magnets, and rechargeable batteries. However, the limited supply of REEs and the significant environmental impact associated with their extraction and concentration have prompted countries to explore recycling options for REE-bearing waste. Despite this, the lack of an efficient recycling method remains a challenge. This study proposes a chemical-based approach towards the recovery of rare earth oxides (REOs), which facilitates a clean separation of REOs with purities exceeding 99.1 wt% and 97.1, along with recovery rates more than 99.3 wt% and 97.1, respectively, from permanent Nd-Fe-B magnets and Ni-MH batteries. Initially, REEs (La, Ce, Nd, Pr, Dy, and Sm) were thermally isolated from Ni- and Fe-based metallic alloys, while still containing impurities. The impurities were subsequently removed via an oxalate chemical separation. Thermodynamics of REE oxalate formation indicated that the precipitation of pure REE oxalates occurs only at pH≈0.0. As the pH increases, impurities such as Ni are introduced into the REO products. The abundance of C2O42- decreases the selective separation, whereas HC2O4- recovers REEs from the leachate at pH≈0.0. The proposed pH range, as indicated by the speciation plots, not only restricts the trace of contamination but also maximizes the efficiency of the process. XPS analysis of the chemically isolated REOs indicated no sign of major impurities. The pure REOs recovered in this study can be used as a high-purity precursor for other applications. Overall, this chemical-based approach offers a promising method for recycling REEs, contributing towards meeting the increasing demand for these critical elements.

RARE EARTH METALS: KEY COMPONENTS OF MODERN TECHNOLOGIES

Purpose. The aim of the article is to conduct a comprehensive analysis of the supply routes for rare earth elements and forecast the development of the market for these elements in the current conditions arising from the war and other factors. Methodology of research. The scientific research methodology was used in the process of writing the article to determine generalised synthetic indicators on strategic ways of development and diversification of rare earth elements supply, as well as statistical and graphical methods to analyse the rare earth elements market and forecast supply and demand using time series. Graphs were used to visualise this data. Findings. It has been found that lithium, cobalt, neodymium and graphite, as well as other elements, are becoming increasingly important in modern technologies and everyday life, which leads to an increase in demand for these rare earth elements. The market for rare earth elements is analysed and demand is forecasted to grow in the future due to the development of green technologies and high-tech devices. The ways of developing and diversifying the supply of rare earth elements are investigated, which made it possible to consider them critical due to possible shortages, supply restrictions and the lack of local concentrations for mining. The global REE market is dominated by Chinese production of REE oxides. That is why, in order to avoid potential risks in the supply of rare earth materials, it is important to consider alternative sources and modern processing technologies to meet demand and ensure further production of rare earth elements. Originality. The article analyses the ways of supplying rare earth elements and their important role in modern technologies. A forecast is made, with an analysis of the market for rare earth materials, which will grow in connection with the transition to a climate-neutral economy. The work is relevant because it is the first to analyse the integrated use of rare earth elements in technologies such as lithium-ion battery technology, fuel cell (FCs) technology and permanent magnet motors. Potential risks in the supply of rare earth materials were determined and ways to avoid them were proposed. Practical value. The practical significance of this research is that in the 20th century, rare earth elements became a key to the production of electronics and other technologies. China, which has significant REE resources, controls a large share of global production, which leads to geopolitical tensions in the supply sector. The results of the study can be used to analyse and forecast the ways of supplying rare earth materials, as well as to solve issues related to future challenges and the development of competition for resources. Key words: rare earth elements (REEs); critical material; lithium-ion battery technology; Fuel cells (FCs) technology; permanent magnet motors; statistical method; forecasting.