Electrolytic Separation of Iodine from LiCl–KCl–LiBr–LiI Melt and Recovery of Iodine Gas with Copper

Abstract

The separation and recovery of iodine from LiCl–KCl–LiBr–LiI melt was investigated at 723 K. Cyclic voltammograms at a glass-like carbon electrode showed that I2 gas generates at more negative potential compared with Cl2 and Br2 gases. Potentiostatic electrolysis for I2 gas generation was conducted at glassy carbon and Au electrodes, where the generated I2 gas was collected by a Cu mesh placed at the top of the cell. XRD confirmed that the Cu mesh changed to CuI. At a glass-like carbon electrode, recovery efficiencies of iodine were 64% and 97% at 3.2 V and 3.3 V vs. Li+/Li, respectively. The recovery efficiency at an Au electrode was 93%. However, a part of the Au electrode dissolved into the melt. Finally, a continuous recovery method was proposed, in which the generated I2 gas was recovered by several independently recoverable Cu meshes packed in a borosilicate gas outlet tube.