Abstract: A process for removing alkaline earth metal impurities (e.g. calcium and magnesium ions) from an aqueous alkali metal chlorate solution which includes adding sufficient alkali metal carbonate or hydroxide or both to the impure solution to raise the pH to above 9 and form alkaline earth metal precipitates which are then removed from the pH-adjusted solution (e.g. by microfiltration). This process can lower the level of these impurities from about 1-20 ppm to less than about 0.3 ppm or less.

Abstract: A process for fabricating a porous, high surface area electrode and the use of that electrode in an electrolytic cell for manufacturing chlorine-free chlorine dioxide from dilute alkali metal chlorite solutions in a single step is disclosed. The electrolytic cell uses a porous flow-through anode and a cathode separated by a suitable separator.

Abstract: An aqueous solution of chloric acid and alkali metal chlorate is produced in an electrolytic cell having an anode compartment, a cathode compartment, and at least one ion exchange compartment between the anode compartment and the cathode compartment, in a process which comprises:a) feeding an aqueous solution of an alkali metal chlorate to the ion exchange compartment,b) passing hydrogen and alkali metal ions from the anode compartment through a cation exchange membrane into the ion exchange compartment, wherein the hydrogen ions displace alkali metal ions to produce an aqueous solution of chloric acid and alkali metal chlorate,c) passing alkali metal ions from the ion exchange compartment into the cathode compartment,d) electrolyzing the aqueous solution of chloric acid and alkali metal chlorate in the anode compartment to produce an aqueous solution of chloric acid, alkali metal chlorate, hydrogen ions and perchlorate ions as a minor constituent.