Rare Earth Exchanges

Electric Field-Assisted Rare Earth Elements Mining

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Highlights

  • Researchers have developed an innovative electric field-assisted mining technique.
  • The technique achieves up to 95% rare earth element extraction with minimal environmental impact.
  • This new method significantly reduces harmful emissions and eliminates toxic chemicals traditionally used in rare earth element mining.
  • Field tests in southern China demonstrate the technology’s potential to revolutionize sustainable metal extraction.
  • The method uses flexible electrodes and advanced electrokinetic processes.

Rare earth elements (REEs) are essential to produce high-tech devices and green energy technologies, from smartphones to wind turbines. However, mining these critical materials has long been associated with significant environmental damage. Recent research highlights an innovative and eco-friendly technique called electric field-assisted mining, offering hope for a more sustainable future. Today, January 6 we have news about an alternative mining technology that is highly promising.           

Research has been ongoing since at least 2023

According to a study published (opens in a new tab) in Minerals Engineering back in 2023, electric field-assisted mining harnesses the electrokinetic phenomenon to remove light rare earth elements like cerium, lanthanum, and neodymium from soil. Researchers Pires, Ponte, Grassi, and their colleagues demonstrated how variables such as electric field strength and electrolyte concentration significantly influence the extraction process.

Using a weak organic acid, acetic acid, and an electric field strength of 1.0 V/cm, the researchers achieved promising results: mining efficiencies of 78.5% for cerium, 47.7% for lanthanum, and 35.1% for neodymium. This process consumed only 6.5 watt-hours of energy over a 240-hour experiment.

The researchers emphasized the eco-friendliness of this technique, as it operates under mild conditions and avoids the harsh chemicals typically used in traditional mining. By integrating statistical analysis and response surface modeling, the study provides a robust framework for optimizing the extraction process, paving the way for wider adoption of electric field-assisted mining.

Scaling up

While the Minerals Engineering study focused on laboratory-scale experiments, a paper published (opens in a new tab) January 6 in Nature Sustainability advanced the conversation by examining the technique’s potential for industrial-scale application. The research team addressed challenges such as electrode reliability and flow leakage, ultimately achieving a remarkable 95% recovery efficiency for REEs from 5,000 tons of ore.

One of the study’s innovations was the development of a voltage gradient barrier strategy, which uses electroosmosis to enhance the electrokinetic process. This strategy not only improved efficiency but also significantly reduced the environmental footprint. For instance, ammonia emissions—a common byproduct of conventional mining—were cut by 95%, greatly minimizing the risk of water and soil contamination.

The study also highlighted the economic viability of the method. Compared to traditional mining techniques, which rely on toxic chemicals and generate massive waste, electric field-assisted mining offers a cleaner and cost-effective alternative. The researchers concluded that this technique could revolutionize the industry, making the extraction of rare earth elements both greener and more sustainable.

A case study in southern China

Building on the findings from Nature Sustainability, an article (opens in a new tab) in New Scientist from January 6 showcased a real-world application of this technology. At a rare earth deposit in southern China, scientists led by Jianxi Zhu from the Guangzhou Institute of Geochemistry implemented a novel approach using flexible, plastic electrodes. These electrodes, inserted into drilled holes 22 meters deep, created an electric field that guided rare earth ions toward collection points.

To dissolve and separate the rare earth elements, the team injected ammonium sulfate into the ore. Once the electric field was activated, the elements were concentrated near the positively charged electrodes and subsequently transferred to treatment ponds for further purification. This method achieved a 95% efficiency rate in extracting REEs, far surpassing the typical 40-60% efficiency of traditional chemical processes.

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