Development of technology for recovering lithium from seawater by electrodialysis using ionic liquid membrane

Hoshino, Tsuyoshi

The tritium as a fuel for fusion reactors is produced by the reaction of lithium-6 (Li) with neutron in tritium breeding material. However, Li is one of 31 rare metal elements. Furthermore, as a means of addressing global warming, the world is increasingly turning to the use of Li-ion batteries in electric vehicles and as storage batteries in the home; therefore, there is a growing need for Li. In view of Japanese high dependence on imports for material resources, the securing of enough Li resources is an important policy for domestic industry in Japan. We proposed new method for Li recovery from seawater. The method involves the use of an ionic liquid through which only the Li ions in seawater and not the other ions, including Na, Mg, Ca and K, permeate from the anode side to the cathode side during electrodialysis. Thus, the Li ions become concentrated on the cathode side and can be recovered. With both ends of an ionic liquid covered with a SELEMION to prevent outflow of the ionic liquid, Li concentration increased from 4.5% after 2 h to 11.0% after 24 h with an applied electric voltage of 2 V.