Working principle of electrokinetic mining technology. Credit: Nature Sustainability (2025). DOI: 10.1038/s41893-024-01501-9
A team of metallurgists and geochemists from the Guangzhou Institute of Geochemistry, in collaboration with mechanical engineers from the Chinese Academy of Sciences, improved on previous electrokinetic mining techniques by scaling them up to industrial levels. In a paper published in Nature Sustainability, the group describes the changes they made to the system and the results of tests carried out at the mine.
Modern technology relies on multiple rare earth elements, which are used, for example, in EVs, smartphones, and computers. Unfortunately, mining such elements is not very environmentally friendly. Huge machines are used to excavate soil and rock from large mines, where it is mixed with water and a number of toxic chemicals to extract the necessary elements.
This process produces thousands of tons of toxic waste. A team in China has been working for several years to develop a cleaner method of extracting the elements. This involves generating an electric field underground that brings the desired elements closer together and concentrates them, allowing for an easier and cleaner separation process.
This new technology works thanks to conductive plastic electrodes (CPE) developed by the team. Each is made from a mixture of plastic and conductive materials and can be cut to the required length. When ready for use, drill multiple holes and drop individual CPEs into each hole. Ammonium sulfate is then injected into the deposit where all CPE is installed.
The electrodes are powered by an external power source. This creates an electric field in the deposit between the positively and negatively charged electrodes. The charged field can move the rare elements toward the negative cathode and concentrate them, removing only those parts of the deposit that hold the concentrated elements.
Testing at a site with 176 CPEs showed the process reduced ammonia emissions by 95%. The researchers also found that the technology was 95% efficient at extracting rare earth elements from a given mine, compared to traditional techniques that tended to achieve efficiencies of 40-60%. It is said that this is a significant improvement. The researchers point out that to make the process cleaner, renewable power sources should be used, as it uses much more electricity than traditional techniques.
Further information: Gaofeng Wang et al, Industrial-scale sustainable rare earth mining enabled by electrokinetics, Nature Sustainability (2025). DOI: 10.1038/s41893-024-01501-9
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Source: Electrokinetic rare earth mining technology scaled up to industrial level (January 7, 2025) from https://techxplore.com/news/2025-01-electrokinetic-rare-earth-technique-upscaled.html 2025 Retrieved January 9, 2016
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