Molten salt membrane process for chlorine recovery

A novel molten salt electrochemical process has been developed to convert hydrogen chloride (HCl) to chlorine for recycle into industrial chlorination processes. The process, which utilizes electrochemical membrane separation, was previously shown to produce HCl conversions up to 96%. Resulting cross-cell potentials were typically 3.0-3.5 volts when current was applied up to the stoichiometric level. More recently cyclic voltammetry was used to investigate the reduction of HCl and water in a free molten salt electrolyte. Hydrogen chloride reduction peak current densities for the LiCl-KCl-CsCl electrolyte system were found to be higher than those reported previously for the LiCl-KCl system. These results are attributed to the enhanced HCl solubility in the melt due to the addition of CsCl. Water reduction appeared to be kinetically hindered, therefore its presence in HCl process streams is not expected to compromise HCl removal and current efficiency.