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Electrodialytic process for the conversion of impure soda values to sodium hydroxide and carbon dioxide

  • US 4,238,305 A
  • Filed: 10/29/1979
  • Issued: 12/09/1980
  • Est. Priority Date: 10/29/1979
  • Status: Expired due to Term
First Claim
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1. A process for the production of high strength, high purity NaOH and CO2 from soda values in an electrodialysis cell having an anode and a cathode compartment separated by base and acid zones, which comprises the steps of:

  • (a) introducing an aqueous soda solution having NaHCO3, Na2 CO3, trona or mixtures thereof to an acid zone of the electrodialysis cell located between a cation permselective face of a bipolar membrane and one face of a cation permselective membrane;

    (b) introducing an aqueous NaOH solution to a base zone of the cell located between an anion permselective face of a bipolar membrane and the other face of said cation permselective membrane;

    (c) passing direct electric current through the electrodialysis cell thereby producing H2 CO3 and CO2 gas from the soda solution in the acid zone and producing a NaOH-enriched stream in the base zone;

    (d) withdrawing the NaOH-enriched product stream from the base zone; and

    (e) withdrawing H2 CO3 and CO2 gas and partially depleted soda solution from the acid zone.

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