Can China’s caesium-from-brine tech cut reliance on Canadian, Australian ores?

Chinese researchers have pioneered an environmentally friendly method for extracting caesium from brine, a development that could significantly enhance China's domestic supply of this vital strategic resource. Caesium is crucial for advanced technologies, including atomic clocks in satellites and thermal imaging sensors for missile systems. Both China and the United States are major consumers of caesium, yet they largely depend on imports.

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Caesium, a rare metal, is a critical strategic resource used in satellite atomic clocks, missile thermal imaging sensors and advanced speciality glass.

Currently, commercial deposits of caesium are primarily found in ores and brines, with significant sources located in Canada, Zimbabwe, Namibia, and Australia. While China possesses considerable domestic reserves, much of it is locked in brine, making processing difficult. Existing methods face challenges due to caesium's low concentration in brine and the presence of interfering ions like sodium, potassium, and magnesium.

A research team led by Zhou Yongquan at the Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, has proposed a stable and efficient extraction method detailed in the Chemical Engineering Journal. Their innovative approach utilizes a sieve-like material designed to selectively trap caesium ions, effectively acting as a magnet for the element. This process allows caesium to be "sieved" out as brine passes through a column packed with the material.

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The team developed a sieve-like mechanism to trap caesium, creating a material that selectively acts like a magnet for caesium ions.

This breakthrough holds the potential to diversify China's industrial supply chain for caesium. The developed material is also reusable, offering a sustainable and efficient solution for extracting the rare metal from salt lake brines, addressing long-standing challenges in scalable caesium extraction.

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When brine is passed through a column packed with this material, caesium ions are “sieved” out. Moreover, the material can be repeatedly reused.