Abstract: The installation for separating a multivalent cationic species from a solution comprising this multivalent cationic species and lithium comprises a capture device (3) having an entry (2) and an exit (4). The capture device (3) comprises, between the entry (2) and the exit (4), a microfibre product (12) with a higher affinity for multivalent cations than for monovalent cations. The installation comprises a circulation system (5) adapted to circulate the solution from the entry (2) to the exit (4) in contact with the microfiber product (21), the microfibre product (21) capturing said multivalent cationic species.