COLEX process

In the US, several chemical exchange methods for lithium isotope separation have been under investigation in the 1930s and 1940s to develop a process for lithium-6 production, so that tritium could be obtained for thermonuclear weapons research.

[2] Stockpiles of lithium-6 and lithium-7 from that period have been available until recently to meet the relatively small domestic and world demand[3] Since then, due to environmental concerns, the US has stopped lithium enrichments operations in 1963.

In the beginning of the 21st century, the steady increase of lithium world production is mainly stimulated by the demand of Li-ion batteries for electric vehicles.

[6] From a technical and economical point of view, the COLEX separation has been so far the only method that enables industrial scale production of enriched lithium at minimal costs.

[7] In spite of the health and environmental concerns associated with processes based on mercury, some research is still being done on the COLEX separation along with cleaner lithium enrichment methods.

[7] Russian enrichment capacities focus on lithium-7 production by electrolysis of an aqueous lithium chloride solution using a mercury cathode, which is thus different from the COLEX process.

However, with the upswing in research in the general area of fusion reactor technology (ITER, DEMO) there has been renewed interest during the last decade in better processes for 6Li-7Li separation, especially in Japan and the US.