Lithium recycling from artificial leachate of spent lithium-ion batteries using track-etched membranes for hybrid electrobaromembrane method

Abstract

Lithium recycling is still poorly developed, but an important source of raw materials for the production of lithium salts. The hydrometallurgical technologies are usually employed to extract lithium from spent lithium-ion batteries. Reagent free membrane technologies such as electrobaromembrane method (EBM) can be used at this stage for the separation of Li+ ions and Co2+, Ni2+, Mn2+. The essence of the method is the simultaneous use of an opposing electric field and a pressure gradient in the device. Non-selective track-etched membrane with wide pores is used for ions separation. The selectivity of EBM separation is achieved due to the different mobility of the separated ions in the electric field. Under optimal conditions, this allows some of the more mobile ions to overcome the barrier of the oncoming convective flow, while others follow it. For the first time, the EBM method was used for long-term extraction of Li+ ions from an artificial leachate solution of spent LIBs. A solution containing the main macro components of typical leachate was processed at 0.3 bar and 125 A/m2 for 50 h. The fluxes of separated Li+, Co2+, Ni2+ and Mn2+ ions through the track-etched membrane were as follows 0.2, −0.02, −0.03 and − 0.08 mol/(m2 × h), respectively. A modification of the track-etched membrane with PDADMAC, which carries a positive charge, has been approved, which makes it possible to increase the rejection of doubly charged ions for more effective lithium isolation.