Electrodialytic process for producing an alkali solution

An electrodialytic process for producing an alkali solution from a salt comprising the steps of:

• a. separating at least one central ion exchange compartment from a first adjacent ion exchange compartment by a bipolar water ionizing electrode on the side of the central ion exchange compartment closer to a cathode and from a second adjacent ion exchange compartment by a first cation permselective membrane positioned on the side of said central ion exchange compartment closer to an anode;
• (b) separating a second adjacent ion exchange compartment and an anode compartment by a second cation permselective membrane;
• (c) separating a first adjacent ion exchange compartment and a cathode compartment by a third cation permselective membrane;
• (d) feeding a sodium carbonate solution to the first adjacent ion exchange compartment and the second adjacent ion exchange compartment;
• (e) feeding an anolyte solution into the anode compartment;
• (f) feeding a catholyte solution to the cathode compartment;
• (g) generating hydrogen ions in the anode compartment and transporting those hydrogen ions through said second cation permselective membrane to said second adjacent ion exchange compartment to produce carbon dioxide;
• (h) transporting sodium ions through the first cation permselective membrane from said second adjacent ion exchange compartment to the central ion exchange compartment;
• (i) reducing water in the central ion exchange compartment with the bipolar water ionizing electrode;
• and
• (j) combining the transported sodium ions with hydroxyl ions produced in the central ion exchange compartment to form sodium hydroxide.