Process for Producing Lithium Iodide Cleanly through Electrodialysis Metathesis.

ABSTRACT

Lithium iodide is commonly used in the production of batteries and drugs. Currently, the neutralization method is the primary means of producing lithium iodide. This method involves using hydriodic acid as a raw material, adding lithium carbonate or lithium hydroxide, and obtaining lithium iodide through evaporation and concentration. However, hydriodic acid is chemically unstable. Its preparation can lead to explosive accidents and encountering high temperatures generates toxic iodine vapors. These limitations restrict its industrial production. The study evaluates the impact of membrane stack configuration, operating voltage, and initial concentrations and volume ratios of reactants on the production process. Electrodialysis metathesis, characterized by a simpler process flow, lower energy consumption, and environmental benefits, emerges as an effective technique for electrically driven membrane separation in lithium salt production and purification. Under the specific conditions of a C-C-A-C-A-C membrane stack configuration, operating voltage at 25 V, initial potassium iodide concentration at 0.4 mol/L, initial lithium sulfate concentration at 0.2 mol/L, and a 11 volume ratio of product liquid to raw material liquid, the method achieves a lithium iodide purity of 98.9% with a production cost of approximately 0.502 $/kg LiI.