INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN APPLIED SCIENCE (IJRIAS)
ISSN No. 2454-6194 | DOI: 10.51584/IJRIAS |Volume X Issue X October 2025
www.rsisinternational.org
Page 996
Comparative Analysis of Traditional and Innovative Methods for Rare
Earth Element Extraction
Kukula Iuliia*
PhD Candidate in Sustainable Energy, Arizona State University, USA, Tempe
*Corresponding Author
DOI:
https://dx.doi.org/10.51584/IJRIAS.2025.1010000082
Received: 05 October 2025; Accepted: 10 October 2025; Published: 08 November 2025
ABSTRACT
This article addresses the application of traditional and innovative methods for rare earth elements extraction,
with a focus on their technological efficiency and environmental safety. It discusses approaches based on
hydrometallurgical and pyrometallurgical processes, as well as emerging solutions, including bioleaching,
hydrogen reduction, electrochemical recovery, the use of ionic liquids, and membrane-sorption technologies.
The study emphasizes that modern methods offer significant potential for reducing the carbon footprint and
enhancing the resource efficiency of the sector. The comparative analysis highlights the need to integrate both
traditional and innovative solutions into sustainable production chains, especially in the context of growing
global demand for rare earth elements and the increasing importance of technological independence.
Keywords – rare earth elements, environmental safety, hydrometallurgy, pyrometallurgy, bioleaching, hydrogen
reduction, electrochemical metal recovery, membrane-sorption technologies, ionic liquids.
INTRODUCTION
Rare earth elements (REE) are a collection of seventeen chemical elements that share certain physicochemical
properties, including excellent magnetic, optical, electrical, and catalytic qualities. These render them crucial
material during the production of high-technology products – from electronics and permanent magnets to devices
for renewable energy, including wind turbines and rechargeable batteries. Given the strategic importance of REE
to defense, aerospace, medical technologies, and the green economy, environmental safety and sustainability of
their extractive processes have become of utmost significance.
Conventional REE separation operations, which largely utilize pyrometallurgy and hydrometallurgy
technologies, are marked by their high release of dangerous compounds, energy use, and production of dangerous
wastes. The objective of the study is to make a comparative assessment of traditional and new methods of REE
production from the perspective of environmental friendliness and technological efficiency and to forecast the
potential of large-scale industrial exploitation of new solutions.
Main Part. Characteristics of Traditional Ree Extraction Methods
Modern industry is facing increasing pressure on its mineral resource base, particularly in the segment of
strategically important metals, which includes REE. Their extensive use in high-tech and energy sectors makes
these resources critically important for ensuring technological sovereignty and industrial security. In the context
of market globalization and growing competition for access to REE sources, the resilience of supply chains and
the stability of raw material provision acquire strategic significance [1]. According to data from the analytical
firm The Business Research Company, the global rare earth metals market reached $5.62 billion in 2024.
Furthermore, it is expected to demonstrate steady positive growth in the medium term, with a projected CAGR
of 10.98 % (fig. 1).
INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN APPLIED SCIENCE (IJRIAS)
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Fig. 1. Global rare earth metals market size, billion dollars [2]
The rapid growth in demand and the expansion of the global REE market are inevitably accompanied by an
increase in extraction and processing volumes. This, in turn, brings to the forefront the issues of technological
efficiency of existing extraction methods and their environmental impact. Against this backdrop, a critical
analysis of traditional methods – still dominant in global raw material processing practices – gains particular
importance.
Traditional technologies for REE extraction are primarily based on hydrometallurgical and pyrometallurgical
processes (table 1).
Table I Traditional technologies for REE extraction [3, 4]
Method
Process principle
Typical reagents / conditions
Hydrometallurgy
Leaching of metals from ores using
acidic or alkaline solutions.
Sulfuric, nitric, hydrochloric acids;
temperature 60-200 °C; pressure up to 10 atm.
Pyrometallurgy
Thermal treatment of raw materials
through smelting, reduction, and
refining in furnaces.
Coke, fluxes, reducing agents; temperature
1200-1600 °C.
Despite the high efficacy of these technologies in terms of extraction yields of target components, such methods
entail serious environmental impacts. Hydrometallurgy – involving acidic or alkaline leaching – requires
substantial amounts of aggressive chemical reagents, notably sulfuric, nitric, and hydrochloric acids, as well as
sulfates and chlorides. According to experimental studies, when processing rare earth mining tailings, acid
consumption may reach up to 11 kg of hydrochloric acid and 29 kg of nitric acid per ton of starting material,
while the yield of REE is less than 0.5 kg per ton – highlighting the low mass efficiency of target product relative
to reagent use [5].
Use of acids and salts in the process technology generates liquid industrial effluents containing dissolved heavy
metals, radioactive isotopes such as thorium and uranium, and ions of REE themselves. Inefficient or inadequate
treatment of these wastewaters may lead to surface and groundwater contamination, deposition of toxic species
in biosphere and soil, and serious risk to environmental quality and long-term sustainability of water resources
in process and mine locations.
Pyrometallurgical processes account for the majority of the energy balance in REE production and also
contribute significantly to CO₂ emissions. They also result in the production of HF gases, particulate emissions,
and sulfur-containing gaseous species, which, if not contained within the process, can be released to the
atmosphere and pollute the immediate environment.
INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN APPLIED SCIENCE (IJRIAS)
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Significant attention in evaluating traditional methods should be given to the resource intensity of these
processes. According to one study, the REE rock-to-metal ratio can be anywhere from 16 to 3,600 tons of ore
per ton of product, depending on the deposit type and the processing technology utilized. Such figures involve
ore beneficiation and enormous quantities of water, chemical reagents, and electricity. With accompanied high
capital and operating costs, this can render production financially unviable without more subsidies, particularly
under conditions of price uncertainty in the international rare earth market.
Another problem is posed by geochemical risks concerning the mineralogical character of REE ores. Rare earths
are usually associated with naturally occurring radioactive elements such as uranium and thorium. Mobilization
on leaching can lead to radioactive contamination of process streams and necessitate special waste disposal and
worker protection precautions.
Thus, traditional REE extraction processes, as industrially advanced and as well-established as they may be,
have a significant environmental price tag and put a heavy burden on the economy [6]. In 2024, the U.S.
Geological Survey (USGS) reports, the USA produced 45,000 metric tons of rare earth mineral concentrates at
the Mountain Pass mine, but just 1,300 metric tons were processed into compounds and metals within the
domestic country. This would indicate the continued dependence on foreign supplies, with roughly 80 % of the
REE compounds and metals that are domestically consumed being imported.
Innovative Approaches To Ree Extraction
According to data from the USGS, global REE production reached approximately 390,000 metric tons in rare
earth oxide (REO) equivalent in 2024, reflecting a steady upward trend. The primary contributors to this increase
were China, the USA, as well as Nigeria and Thailand, which have demonstrated dynamic growth in REE mining
activities (fig. 2).
Fig. 2. REE mine production by country in 2023 and 2024 (in metric tons, REO equivalent [7]
At the same time, imports of REE to the USA decreased by 11 %, indicating a shift toward partial localization
of production and a reduction in dependence on external suppliers. These trends – increased production,
restructuring of supply chains, and tightening environmental regulations – underscore the growing relevance of
implementing alternative, sustainable REE extraction technologies capable of ensuring processing efficiency
with minimal environmental impact [8].
Innovative REE extraction methods are being actively explored both in research institutions and within pilot-
scale industrial facilities. Their development is driven not only by the need to improve efficiency and selectivity,
but also by the pursuit of technological diversification and reduced reliance on conventional resources (table 2).
INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN APPLIED SCIENCE (IJRIAS)
ISSN No. 2454-6194 | DOI: 10.51584/IJRIAS |Volume X Issue X October 2025
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Table 2 Innovative methods for REE extraction
Method
Brief description
Bioleaching (biotechnology)
Utilization of microorganisms to leach REE from ores and
waste under mild temperature and chemical conditions.
Hydrogen reduction
Hydrogen is used to reduce REE oxides, producing water
vapor rather than carbon emissions.
Ionic liquids and deep eutectic solvents
Use of alternative low-toxicity solvents instead of traditional
acids for selective REE extraction.
Electrochemical extraction
Separation or precipitation of REE through electric current,
frequently utilizing renewable energy sources.
Sorption and membrane technologies
Selective REE extraction using specialized membranes or
sorbents based on carbon or polymeric materials.
The development of these techniques enables the construction of integrated and sustainable technological chains
for both primary raw materials and anthropogenic sources. Hybrid techniques – combining a number of
techniques within one cycle, e.g., initial biodegradation, selective sorption, and electrochemical precipitation –
are especially important. This opens up the possibility of using modular plants for decentralized REE processing
with minimal environmental effects, especially in regions of poor infrastructure.
Although the environmental benefits of novel REE extraction processes are widely recognized, it is essential to
underpin these with quantitative metrics based on life-cycle assessment (LCA). By way of illustration, mixed
REO production was estimated to emit 258-408 kg CO₂‑eq and require 270-443 MJ primary energy per kg of
REO, which underscores the carbon intensity of conventional routes [9].
Besides, Schreiber et al. (2021) in their review highlight that many LCIs lack crucial data on wastewater
emissions, radioactive tailings, and indirect emissions, resulting in high uncertainty in environmental impact
research [10]. A good example is provided by Wan, Zhou, and Xue (2022), who conducted a carbon footprint
analysis of mixed rare earth oxides (REOs) produced from ionic rare earth resources. Their findings indicate that
the carbon footprint to yield 1 kg of mixed REOs is 17.8-24.3 kg CO₂-equivalent with an uncertainty range of
approximately 15.54 %, depending on process parameters and recovery efficiency [11].
More recent articles from 2023-2025 provide up-to-date benchmarks for new and secondary‑source extraction
methods. A white paper by Western Digital and CMR (2023) reports a 95 % reduction of greenhouse gas
emissions in the recovery of REEs from end‑of‑life hard drives compared to conventional mining [12].
While novel REE extraction methods show apparent technological and environmental advantages, their
application in the real world is not completely without limitations. In particular, certain approaches still suffer
from constraints in recovery efficiency from low-grade and complicated ores, as well as operational challenges
of modular and decentralized systems. These include process stability issues, material compatibility, and
maintenance requirements, which could affect scalability and long-term operation.
Besides technological challenges, enhanced utilization of new REE extraction methods is also vulnerable to
policy and regulatory environments, which vary immensely from one place to another. For instance, the
European Union encourages green extraction technologies heavily through initiatives such as the Critical Raw
Materials Act and Horizon Europe, which offer favorable environments for innovation-led initiatives. Strategic
initiatives in the United States have been directed towards enhancing local production and reducing import
dependence, as stimulated by recent Department of Energy programs and infrastructure investment initiatives.
Despite these programs providing solid institutional backing, the diversity of regulatory regimes between state
and federal levels can affect the coordination and approval timeframes of projects. Such regional variation
emphasizes the necessity of balancing technological capability with specific legal, economic, and administrative
contexts where such solutions are meant to be used.
INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN APPLIED SCIENCE (IJRIAS)
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Comparative Analysis Of The Efficiency Of Traditional And Innovative Ree Extraction
Conventional technologies such as pyrometallurgy and hydrometallurgy remain industrially robust with high
recovery rates but are associated with high environmental footprint, high energy consumption, and occupational
health issues. New technologies, however, are not yet widely applied on large scale but are increasingly being
implemented in industry due to their flexibility, lower carbon footprint, and compatibility with resource
efficiency principles (table 3).
Table 3 Comparative characteristics of traditional and innovative REE extraction methods
Traditional methods
Innovative methods
High recovery from rich ores;
reduced efficiency for low-grade
ores.
Stable yields from low-grade REE
ores; potential use of waste and
secondary resources.
High (especially after purification
stages); stable under industrial
control.
High (in selective methods: ionic
liquids, membranes).
High, especially in pyrometallurgy;
depends on temperature and
reagents.
Lower due to milder conditions;
possible integration with RES.
High – due to fuel combustion,
emissions, acidic waste, slag
generation.
Low – in closed-loop cycles:
bioleaching, sorption,
electrochemical extraction.
High risk (corrosive reagents, dust,
radioactivity).
Significantly lower due to non-
toxic solvents and controlled
processes.
Strong – soil degradation, water
contamination due to heavy metal
emissions.
Moderate to low – reduced
pollutant emissions; better
suitability for strict environmental
regulations.
Limited – tied to raw material and
infrastructure.
High – possibility of modular,
scalable solutions for distributed
and localized production.
Analysis given herein indicates that the choice between the old and new extraction methods is not a choice
between extremes. Rather, it must be made based on a combination of raw material nature, availability of
infrastructure, environmental limitations, and product specifications to be manufactured. Traditional methods
are still feasible in the context of processing bulk high-grade ore, but novel technology has scope to be able to
recover REE from secondary and low-grade ores using lower energy and environmental footprints.
The development of the industry should not occur at the expense of what already exists but through its review
and reconciliation with emerging technological solutions. This is a transition required to ensure long-term
production viability in light of rising world demand and stricter environmental protection requirements.
One of the instances of application of emerging technologies for REE extraction includes the project launched
by the West Virginia Water Research Institute, which received funding from the U.S. Department of Energy. In
a research laboratory in the National Research Center for Coal and Energy (NRCCE) at West Virginia University,
Morgantown, researchers are studying whether REE can be recovered from acid mine drainage (AMD), an
element traditionally viewed as an environmental contaminant. The development of such technologies could not
only generate employment and support the economy of coal-dependent regions but also transform contaminated
sites into strategic resources. The project illustrates the commercial viability of converting regional
INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN APPLIED SCIENCE (IJRIAS)
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environmental risks into sources of critical materials – an especially relevant strategy given the USA’s high
reliance on REE imports.
In 2023, the U.S. Department of Energy announced the results of the first round of project selections under the
FOA-2619 program, funded through the Bipartisan Infrastructure Law [13]. The selected technologies include
the use of ionic liquids, low-temperature metallothermic processes, and pilot facilities with throughput capacities
of up to 500 gallons per minute. Investment in these projects shows the strategic interest of the USA in the
establishment of a domestic high-tech rare earth supply chain and reducing reliance on imports.
Additionally, in 2025, the U.S. Department of Energy launched a unique initiative called Mine of the Future
aimed at large-scale pilot demonstrations of emerging technologies. A key component of this initiative is the
allocation of up to $80 million for the establishment of Mining Technology Proving Grounds – field testbeds
aimed at accelerating the commercialization of new extraction and processing technologies for critical minerals,
including REE [14]. These efforts are designed to improve domestic supply chain strength through the
introduction of sophisticated engineering solutions and reduce the country's dependence on external REE
sources.
One of the illustrations of circular economy use in the case of REEs is the HyProMag USA project. Established
as a joint venture between HyProMag Ltd and CoTec [15] Holdings, the project targets the recycling of spent
neodymium–iron–boron (NdFeB) magnets – one of the key industrial products of REEs, such as neodymium,
dysprosium, and terbium. In demonstration size, approx. 900 kg of recycled NdFeB alloy were already being
produced on pilot plant in Tyseley (UK), while in America the planned capacity is up to 750 metric tons annually
of recycled sintered NdFeB magnets and 807 tons of by-products. According to an external carbon footprint
analysis, HyProMag USA's product range is a prime example of 2.35 kg CO₂-equivalent per 1 kg of finished
sintered NdFeB block, significantly lower than for traditional primary production. The planned production
facility in the vicinity of Dallas–Fort Worth, Texas, is conceived with REE magnet recycling localization and
reduction of logistics costs in mind. The HyProMag USA project is thereby a pragmatic means of implementing
circular principles into the REE industrial process as well as reducing the carbon footprint and enhancing U.S.
resource independence.
Another example of circular economy use in the industry of REE is the business of REEcycle, an American
company that specializes in recycling electronic waste, such as end-of-life NdFeB magnets. The company uses
patented technology through which rare earth element recovery efficiencies of up to 99.8% are made possible,
with neodymium, praseodymium, dysprosium, and terbium being the majority of them. In 2025, the U.S.
Department of Defense invested $5.1 million to support pilot facility construction for REEcycle, highlighting
the national strategic significance of the project to enhance national resource security. Compared with
conventional mining extraction, REEcycle comes with a lower environmental impact through recycling of waste
streams, thereby minimizing dependence on virgin raw material and associated emissions.
Thus, the presented cases confirm that circular economy models and emerging technological solutions can be
effectively integrated into the REE supply chain to enhance sustainability, resource independence, and
environmental performance.
Despite the intensive development of new REE extraction technologies, their technological readiness remains a
bottleneck for industrial implementation at large scale. The majority of technologies are at Technology Readiness
Levels (TRL) 4 to 6, i.e., tested at laboratory and pilot scales but requiring upscaling, standardization, and
demonstration to be economically viable at full-scale production. Foremost among these are the capital intensity
of installations, the challenge of transferring technologies to variable mineral feedstocks, the absence of a
developed regulatory framework, and technological risks in integrating new processes into existing
infrastructure.
For the promotion of localized and sustainable production of REE, government departments and industrial
interests can contemplate the establishment of comprehensive support regimes aimed at encouraging suitable
technological and infrastructural options. Some of the steps that can be adopted are the promotion of public–
private partnerships to dampen investment risk during the initial stages of implementation, as well as incentives
INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN APPLIED SCIENCE (IJRIAS)
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in the form of setting up modular and decentralized processing facilities within regions of richness but with
limited-scale infrastructure. National policies can also impact the development of specialized infrastructure –
i.e., regional REE innovation clusters, recycling facilities, and pilot-scale demonstration plants – subject to
environmental standards and long-term resource security objectives. Additional emphasis on building workforce
training and applied scientific research could further increase domestic capability for sustainable REE production
and processing.
CONCLUSION
The traditional and new technologies of REE extraction represent two alternative technological trajectories, each
with its own logic of development, field of application, and restrictions. After rising global demand for REE as
well as rising need to enhance resource independence, the answer lies not in opposition to such approaches but
in seeking sustainable blends based on raw material quality, infrastructure availability, and environmental and
social considerations. The advanced technologies free the potential for treating complex and second-order
resources in a non-environmentally intrusive way, while traditional methods offer reliability and scalability to
high-grade mineral feedstocks.
The development of the REE sector cannot be a reality without the convergence of scientific studies, government
policies, and industrial practice. Trends today – spanning from demonstration projects and financing initiatives
to pilot-scale usage – are trending toward a new paradigm of REE recovery that is more responsive, adaptive,
and sustainable. Technological efficiency, environmental stewardship, and economic feasibility combined will
determine the competitiveness of solutions in the critical minerals development sector in the long term.
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