China has launched a production line to extract rubidium and caesium from lithium waste, marking what Chinese researchers describe as the world’s first industrial-scale extraction and separation line for low-grade sources of the two metals.
A demonstration line in Jiangxi province, with an annual capacity of 500 tonnes, has achieved stable production, according to the Institute of Process Engineering under the Chinese Academy of Sciences (CAS), reported South China Morning Post.
Rubidium and caesium are critical to aerospace, quantum computing, biomedicine, new energy and other frontier industries. However, neither metal occurs in large quantities as an independent mineral in the Earth’s crust. Instead, they are typically found as associated elements in lithium ores and salt-lake brines, where their concentrations are low and extraction is technically difficult.
By recovering the metals from waste left behind after lithium extraction from ore, China is extending its new-energy industry supply chain while strengthening the domestic supply of rubidium, a strategic rare and precious metal.
How China’s new extraction technology works
The breakthrough is based on a high-efficiency tower extraction system for rubidium and caesium developed by the Institute of Process Engineering under the Chinese Academy of Sciences.
The technology uses differential counter-current extraction to separate the two elements and, according to the institute, has independent intellectual property rights. The research team designed an industrial unit comprising 17 extraction towers in partnership with Jiangxi Ganfeng Lithium and other companies. The unit started up successfully on its first attempt and has operated continuously and steadily since then, according to the institute.
The process can recover more than 98 per cent of the caesium and more than 95 per cent of the rubidium from the material being processed. The resulting caesium carbonate and rubidium carbonate products have purities of more than 99.9 per cent. The demonstration line has a combined annual production capacity of 500 tonnes of rubidium and caesium carbonates. The exact ratio of rubidium to caesium in the output has not yet been disclosed.
Smaller footprint, lower extractant consumption
According to CAS, the system has several advantages, including a smaller footprint, lower use of extraction agents and stronger containment.
A single extraction tower can be up to 15 times as efficient as a traditional extraction tank. The technology also reduces extractant consumption by 40 per cent and cuts the equipment footprint by more than 50 per cent.
How the technology could boost China’s critical-minerals supply
The demonstration line shows that low-grade rubidium and caesium resources occurring alongside lithium can be separated at industrial scale. It also provides a technical model for the larger-scale commercialisation of the process. The approach could allow China to recover valuable metals that were previously lost in lithium-processing waste, effectively creating an additional domestic source without relying solely on new mining. It also extends the country’s existing new-energy production chain beyond lithium itself by extracting additional critical materials from the same resource stream.
The potential importance of the technology could grow as new applications for rubidium and its compounds emerge. Breakthroughs in areas such as perovskite solar cells, solid-state batteries and quantum computing could expand demand for rubidium salts and other compounds.
