Smartphones, electric vehicles and wind turbines rely on environmentally destructive rare earth mining operations. Harnessing electric fields could make this mining more sustainable
By Jeremy Hsu
6 January 2025
Mining for rare earth metals comes with environmental consequences
Joe Buglewicz/Bloomberg via Getty Images
Rare earth elements used in smartphones and electric vehicles could be extracted from the ground more sustainably using electric fields.
Today, most rare earth metals used in electronics are mined by using toxic chemicals to extract the elements from mineral ore. During the mining process, thousands of tonnes of chemical waste are released, which can pollute nearby groundwater and soil. But concentrating those elements together using electric charges could drastically cut the amount of environmentally damaging chemicals needed.
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“Imagine a crowd being guided through a maze by directional lights – similarly, rare earth elements are driven from the ore by the electric field toward specific collection points,” says Jianxi Zhu at the Guangzhou Institute of Geochemistry in China. “This controlled movement ensures efficient mining with minimal environmental disruption.”
Zhu and his colleagues created flexible, sheet-like plastic electrodes – each 10 centimetres wide with customisable lengths – made from non-metallic materials that can conduct electricity. At a rare earth deposit in southern China, they inserted 176 electrodes into individual holes drilled 22 metres into the rock.
Next, they injected ammonium sulphate, a type of inorganic salt, into the ore to dissolve and separate out the rare earth elements as charged ions. They then activated the electrodes to create an electric field between positively and negatively charged electrodes. That electric field moved the rare earth elements toward the positively charged electrodes, concentrating them together. The elements could then be transferred to treatment ponds for additional purification and separation processes.