China has inaugurated a demonstration production line in Jiangxi province capable of extracting rubidium and caesium from lithium processing waste, marking a significant technological advancement in the recovery of these rare metals. The facility, developed by the Institute of Process Engineering under the Chinese Academy of Sciences (CAS) in collaboration with Jiangxi Ganfeng Lithium and other partners, has an annual output capacity of 500 tonnes of rubidium and caesium carbonates.

Rubidium and caesium are critical materials used in advanced technologies, including aerospace, quantum computing, biomedicine, and new energy sectors. However, these elements rarely occur in concentrated forms and are typically found in trace amounts within lithium ores and salt-lake brines, making their extraction challenging and costly. China’s move to recover these metals from lithium waste thus represents an effort to secure supply chains for strategically important materials while extending the value chain of its lithium industry.

According to CAS, China's domestic reserves of rubidium oxide are estimated at approximately 1.16 million tonnes, and caesium oxide reserves at around 140,000 tonnes, largely embedded in low-grade and complex mineral formations. Previously, extraction methods such as high-temperature sulphate roasting resulted in a significant loss of rubidium and caesium, as these metals were trapped in aluminosilicate waste discarded alongside lithium slag.

The newly developed extraction technology employs a high-efficiency tower extraction system based on differential countercurrent extraction principles, reportedly increasing extraction efficiency up to 15 times compared to traditional methods. This approach also reduces chemical extractant use by 40 percent and cuts the equipment footprint by more than half. The industrial setup features 17 extraction towers working continuously since its launch, achieving over 98 percent recovery of caesium and more than 95 percent recovery of rubidium. The resulting caesium carbonate and rubidium carbonate products exceed 99.9 percent purity, meeting commercial quality standards.

China’s limited access to pollucite, the primary industrial source of caesium, has historically necessitated imports from countries like Canada, Australia, and Zimbabwe. With most rubidium and caesium resources in China found within lithium-bearing minerals such as lepidolite and salt-lake brines, this technology offers a viable solution to reduce dependency on foreign sources.

The successful establishment of this demonstration line may pave the way for expanded commercial operations, enabling China to leverage its abundant but complex mineral resources more effectively. The CAS reported that the innovation not only promotes sustainable mineral resource development but also enhances the secure supply of rubidium and caesium, elements increasingly vital to emerging high-tech industries where China holds a leading position globally.