SODIUM-HYDROXIDE AND HYDROCHLORIC-ACID GENERATION FROM SODIUM-CHLORIDE AND ROCK-SALT BY ELECTRO-ELECTRODIALYSIS

An electro-electrodialysis process (EED) is used to generate HCl and N aOH from trade NaCl. The key phenomenon limiting the current efficienc y of this process is proton leakage through the anion selective membra ne. Two new low proton leakage membranes: the ARA and ACM were used. N aOH and HCl solutions with purity higher than 99.9% are obtained, The experimental values of the fluxes for HCl and NaOH are compared with v alues calculated from integration of the Nernst-Planck electrodiffusio n equations. This calculation requires several experimentally determin ed parameters: ionic diffusion coefficients, membrane conductance and amount of sorbed electrolyte. Algerian rock salt from El Outaya is use d to compare electro-electrodialysis and electrodialysis using bipolar membranes.