New Insights into Environmentally Friendly Rare Earth Extraction Using Organic Acids

Highlights

• Researchers discovered that citric acid achieves the highest leaching efficiency (33.07%) for heavy rare earth elements with minimal soil ecosystem impact.
• Organic acids demonstrate a more environmentally friendly alternative to traditional chemical extraction methods for rare earth elements.
• The study shows potential for greener mining practices while addressing challenges in large-scale implementation and economic feasibility.

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A study led by Mengfei Zhao from Jiangxi University of Science and Technology, published in Separation and Purification Technology (2025, Vol. 362), explores the potential of organic acids to extract rare earth elements (REEs) from ion-adsorption type rare earth ores (IAREO) with reduced environmental impact. The researchers hypothesized that organic acids could effectively leach REEs, particularly heavy rare earth elements (HREEs), while preserving soil ecology.

Study Finding

The study compared the performance of acetic, malic, and citric acids, optimized leaching conditions, and analyzed the ecological impacts of these processes.

The findings reveal that citric acid achieved the highest leaching efficiency for HREEs (33.07% for colloidal sediment-phase REEs), followed by malic acid (26.65%) and acetic acid (28.03%). Mechanistic analysis using Visual Minteq (opens in a new tab) simulations and Density Functional Theory demonstrated that differential leaching is driven by complexation effects, with organic acids preferentially targeting HREEs due to their higher charge densities.

Notably, the soil’s ecological structure was minimally impacted, and enzyme activity quickly recovered post-leaching, underscoring the environmental benefits of organic acids compared to traditional ammonium sulfate methods.

Study Limitations

Study limitations include the moderate efficiency of organic acids compared to chemical agents and a lack of large-scale field validation. The study does not address economic feasibility or scalability, critical for industrial adoption. Additionally, while ecological recovery was observed, long-term impacts on soil microbiomes were not explored. This cannot be trivialized.

Moving Forward

This research highlights the potential of organic acids to improve the sustainability of REE extraction, offering a greener alternative for a critical global resource. Further studies are needed to optimize efficiency and assess large-scale applicability, making this approach a promising step toward environmentally conscious mining practices.