China Builds World-First System to Recover Rubidium and Cesium from Lithium Ore

Chinese scientists have built the world's first industrial extraction-column system recovering and separating rubidium and cesium from low-grade resources associated with lithium ores. Developed by the Institute of Process Engineering (IPE) at the Chinese Academy of Sciences (CAS), it has reached stable, high-purity production on the market.

Rubidium and cesium are highly dispersed metals rarely found in economically mineable deposits — cesium from a handful of pollucite mines in Canada and Zimbabwe, rubidium from lepidolite and salt lake brines. Both were discarded during processing of other minerals, despite use in aerospace, precision instruments, 6G communications and quantum technologies.

"The new process recovers rubidium and cesium, which were previously discarded, as byproducts of lithium ore processing," said Wang Yong, the IPE researcher who led the project. A typical ton of lithium concentrate holds about 25 kg of lithium oxide, 7.8 kg of rubidium oxide and 1.8 kg of cesium oxide.

The breakthrough was replacing conventional extraction tanks, which expose organic solvents to air, with sealed extraction columns arranged in four sections — extraction, scrubbing, stripping and de-oiling — for continuous operation. "The columns operate as a fully enclosed system, markedly reducing solvent vapor emissions and odors as well as associated fire risks," Wang said. A single column matches up to 15 conventional stages, cuts solvent use by 40 percent and halves equipment footprint, replacing more than 70 conventional tanks with just 17 columns.

The demonstration line was jointly developed by IPE and Ganfeng Lithium Group Co, the world's largest lithium salt producer, based in Xinyu, Jiangxi province. It has an annual capacity of 500 tons, producing cesium and rubidium carbonate exceeding 99.9 percent purity, with recovery rates above 98 percent for cesium and 95 percent for rubidium. "The entire system was designed and manufactured in China," Wang said. It is already used to separate zirconium and purify phosphoric acid, and is being extended to nickel, cobalt and lithium extraction.