An electrochemical reactor for the extraction of lithium from natural brine has been designed. It comprises two 3D porous packed bed electrodes and a porous separator filled with electrolyte. The electrodes are filled with conducting petroleum coke particles covered respectively with LiMn 2 O 4 selective to lithium ions and polypyrrole selective to anions. It operates in two steps: First, the porous electrodes and the separator are filled with natural brine to extract Li + and Cl − by intercalation and adsorption. Then, after rinsing with water the reactor is filled with a dilute LiCl recovery solution and LiCl is recovered by reversing the electrical current. A mathematical model for the reactor comprising the Nernst-Planck equation and the battery intercalation model has been developed. The model was solved using the finite element method under the COMSOL Multiphysics environment in order to obtain the electrostatic potential and the ion currents and concentrations across the system. Unlike the asymmetric LiMn 2 O 4 /activated carbon super-capacitor, in the lithium extracting reactor the total LiCl concentration decreases in the extraction step and increases in the recovery step. A good agreement between the experimental and simulated potential difference vs. time at constant current validates the model of the reactor.

An electrochemical flow reactor for the extraction of lithium chloride from natural brines has been designed and tested. It comprises two 3D porous packed bed electrodes and an anion exchange membrane. The electrodes were filled with conducting petroleum coke particles covered with LiMn 2 O 4 (anode) in contact with dilute LiCl recovery solution and partly de-lithiated Li 1−x Mn 2 O 4 (cathode) in contact with natural brine. The electrolytes were circulated at constant flow rate through the porous packed bed electrodes and a constant current was passed at the lithium deficient Li 1−x Mn 2 O 4 (cathode) with Li + ion intercalation and de-intercalation at the LiMn 2 O 4 (anode), while a flow of chloride ions operated at the anion selective membrane to compensate charge. In a second step, the electrolytes were exchanged and LiCl was recovered from the lithiated Li 1−x Mn 2 O 4 , now acting as anode. A mathematical model for the flow reactor with the diffusion and migration described by the Nernst-Planck equation, the convective flow of electrolyte and the LiMn 2 O 4 battery intercalation model has been developed using the finite element method under the COMSOL environment.

An electrochemical flow reactor for the extraction of lithium chloride from natural brine has been designed and experimentally tested. The reactor comprises two three-dimen-sional porous packed bed electrodes and a porous separator immersed in electrolyte. The packed bed electrodes were filled with conducting petroleum coke particles covered respectively with LiMn2O4 selective to lithium ion and polypyrrole selective to anions. The reactor operates in two steps: In the first step the porous electrodes and separator were filled with natural brine to extract lithium and chloride by intercalation and adsorption respectively. After rinsing with water, in the second step the reactor was filled with a dilute LiCl recovery solution and by reversing the electrical current LiCl is recovered in the electrolyte. A two dimensional mathematical model which describes the diffusion and migration of different ions in the electrolyte with the Nernst-Planck equation, the convective flow of electrolyte and the lithium ion intercalation in LiMn2O4 has been developed using a finite element method under the COMSOL environment. The model captures the effect of forced convection on the efficiency of lithium extraction due to diffusion gradients in the porous LiMn2O4 cathode and predicts the best operation parameters.