New article on electrodialysis for antisolvent recovery

A new article has been published in the Chemical Engineering Journal, entitled Electrodialysis for efficient antisolvent recovery in precipitation of critical metals and lithium-ion battery recycling. The main person behind the article is PhD-candidate Simon B. B. Solberg, who has just delivered his thesis.

It has proven effective to recover metal compounds from aqueous mixtures by use of antisolvents; organic compounds that induce selective precipitation. A challenge with antisolvents is that they are both costly to produce and recover on an industrial scale. In recycling of lithium-ion batteries and recovering critical metals, we elaborate in the article that electrodialysis can be a competitive method for purifying and recycling antisolvents. We investigate the use of electrodialysis to separate salt and water from a ternary solution of water, KCl and ethanol. A coupled non-equilibrium electrochemical model is developed to understand how such systems may be operated, designed, and which characteristics that are required for the ion exchange membranes. We demonstrate how the water transference coefficients of the membranes should be tuned in the process optimization and why membrane property design is crucial to the success of this concept. Residual mixtures from antisolvent precipitation, with ethanol (EtOH) solvent weight fractions around 0.6-0.7, can be demineralized and the EtOH fraction increased by 0.1-0.2 at an energy requirement of 60-200 kWh per cubic meter of ethanol by use of electrodialysis. In an example application of the concept, aqueous KCl is precipitated by recycled ethanol in a cyclic process, requiring 0.161 kWh per mol KCl. This example case considers complete ethanol rejection by the membranes and abundant water co-transport, characterized by the transference coefficients of 15 and 0 for water and EtOH respectively. The findings pave the way for new applications with aqueous mixtures of critical metals. A sketch of the concept is shown below.