Abstract: A lithium recovery device equipped with a processing tank partitioned into a supply tank and a recovery tank by a lithium ion-conducting electrolyte film, and which, in order to selectively move Li+ to an aqueous solution in the recovery tank from an aqueous solution in the supply tank containing Li+ and metal ions Mn+ which are different therefrom, is also equipped with a first power supply connected between porous-structure electrodes provided so as to respectively contact both surfaces of the electrolyte film with the electrode on the supply tank side as the positive electrode, and a second power supply which connects in series to the negative electrode of the first power supply and in which said negative electrode is connected to a sub-electrode provided at a distance from the electrolyte film inside the recovery tank, wherein the second power supply applies a voltage so as to cause a current to flow from the positive electrode to the electrode.

Abstract: A lithium isotope concentration device includes a treatment tank partitioned in a supply tank and a recovery tank by an electrolyte membrane having a lithium-ion conductivity. The electrolyte membrane is cooled by a cooling device via an Li-containing aqueous solution in the supply tank to have a low temperature at which the Li isotope separation coefficient is larger. A power supply device, connected between electrodes provided on opposite surfaces of the electrolyte membrane, applies a positive voltage to an electrode on a supply tank side.