Ganfeng and CAS run a 500-tonne line for rubidium and caesium from lithium waste

The Institute of Process Engineering at the Chinese Academy of Sciences and Ganfeng Lithium say they have put the world’s first industrial continuous-tower line for rubidium and caesium recovery into stable production in Jiangxi. The plant takes leachate left after lithium is pulled from ore and turns two metals that used to be discarded into carbonate salts already on sale.

Capacity is 500 tonnes a year of rubidium carbonate and caesium carbonate. Product purity is above 99.9 percent. Operating data released with the announcement put overall caesium recovery above 98 percent and rubidium recovery above 95 percent. The hardware is a set of 17 extraction towers, described as a thousand-tonne-scale continuous unit, using a differential counter-current design and a three-phase “gas-liquid-liquid” stripping tower that uses carbon dioxide.

Wang Yong, the IPE researcher who led the project, gave the grade that makes the economics work. A typical tonne of lithium concentrate, he said, holds about 25 kilograms of lithium oxide, 7.8 kilograms of rubidium oxide and 1.8 kilograms of caesium oxide. Those side metals are too thin to mine on their own in most Chinese deposits. China no longer has an independent pollucite mine, the rock that used to feed caesium plants. The metals sit instead in lithium ore and in salt-lake brine. If they stay in the tailings, they are lost. If they ride the same flowsheet, the same tonne of rock pays three times.

Compared with a conventional mixer-settler battery, the team says one tower matches the work of about 15 old tanks, cuts solvent use by 40 percent and halves the plant footprint. The towers are closed, which the engineers present as a safety and emissions gain rather than a slogan. The line is a result of a CAS key-technology programme and Jiangxi’s “2030 Pioneer” special on making peculiar lithium ores usable without leaving a toxic residue.

Ganfeng, based in Xinyu, is the world’s largest lithium-salt producer. Putting the demo on its site is the difference between a paper flowsheet and a product that can be invoiced. Science and Technology Daily reported on 9 September that both carbonates have already gone to market in batches. Later English write-ups on 15 September treated the same plant as a first: a 500-tonne continuous tower line for low-grade rubidium and caesium that actually runs.

The uses sit in a short list of high-spec trades. Caesium and rubidium salts go into atomic clocks, drilling fluids, photoelectric devices, some medical tracers and, in smaller lots, into quantum and aerospace work. None of those markets is large in tonnage. All of them pay for purity above 99.9 percent and for a supply that does not depend on a single pollucite pit.

The strategic reading is obvious and should not be overdone. China already dominates refined lithium. A line that pulls the associated alkali metals out of the same ore reduces import need for two niche but listed critical minerals. It does not, by itself, change the chip or magnet supply chain. What it does change is the waste account at a Ganfeng plant and the bargaining position of anyone who used to sell China caesium from a dedicated mine.

Independent confirmation will come from shipment documents and from whether a second tower set is built at another Ganfeng or Tianqi site. For now the claim to hold is narrower and still useful: a 17-tower train in Jiangxi is making saleable rubidium and caesium carbonate from lithium leachate at the recoveries the academy published.