Electrodialysis and Electrodialysis Reversal for the Concentration of Li Containing Solutions

In this paper, the application of electrodialysis reversal (EDR) in the recovery and concentration of lithium chloride and lithium carbonate solutions is described. Both salts are raw materials that can be used for the production of lithium ion batteries. EDR is characterized by a periodical change of electric polarity and hydraulic flows. This allows the minimization of scaling effects and concentration polarization on the membrane surface during the treatment of lithium containing brines or solutions stemming from lithium ion battery recycling. Lab scale investigations at room temperature were conducted during which the concentrated solution was kept in the cycle throughout the respective investigations, and the diluted solution was exchanged, when a minimum conductivity of 0.08 mS/cm was reached. At the same time, the polarity was changed and the hydraulic flows were reversed. A comparison between EDR and conventional ED at the same operating conditions showed similar current efficiencies of up to 70 % during the concentration of lithium chloride. A maximum lithium chloride concentration in the concentrate solution of about 25 g/l was achieved. The investigations showed the general applicability of EDR for the concentration of lithium chloride and lithium carbonate, which has a restricted solubility in water. Generally, EDR could play a major role in lithium ion battery recycling.