초록 ▼

The formation of sodium sulfate by-product in sulfuric acid-based chlorine dioxide generating processes is decreased and preferably eliminated entirely, by effecting electrochemical treatment of sodium ion-containing feed materials for the generator to remove sodium ions and to add hydrogen ions. So

The formation of sodium sulfate by-product in sulfuric acid-based chlorine dioxide generating processes is decreased and preferably eliminated entirely, by effecting electrochemical treatment of sodium ion-containing feed materials for the generator to remove sodium ions and to add hydrogen ions. Sodium hydroxide may be produced as a by-product. The process is generally applicable to the electrochemical treatment of alkali metal chlorates, alkali metal sulfates and mixtures thereof to produce acidified solutions useful in providing chlorate ion-containing feeds to such chlorine dioxide generating processes or for other purposes.

대표청구항 ▼

A method for the production of chlorine dioxide, which comprises: providing an aqueous acid chlorine dioxide-generating reaction medium containing sulfuric acid and alkali metal ions in a reaction zone, forming an aqueous solution of at least one alkali metal salt from solid phase alkali metal salt

A method for the production of chlorine dioxide, which comprises: providing an aqueous acid chlorine dioxide-generating reaction medium containing sulfuric acid and alkali metal ions in a reaction zone, forming an aqueous solution of at least one alkali metal salt from solid phase alkali metal salt selected from the group consisting of alkali metal chlorate, alkali metal sulfate and mixtures of alkali metal chlorate and alkali metal sulfate, electrochemically acidifying said aqueous solution of at least one alkali metal salt, electrochemically removing alkali metal ion from said aqueous solution to produce an acidified alkali metal salt solution, when said alkali metal salt is selected from the group consisting of alkali metal chlorate and mixtures of alkali metal chlorate and alkali metal sulfate, forwarding said acidified alkali metal salt solution as an acidified chlorate ion-containing solution to said reaction zone to provide chlorate ion and hydrogen ion reactants to said aqueous acid chlorine dioxide-generating reaction medium, when said alkali metal salt is alkali metal sulfate, adding alkali metal chlorate to said acidified alkali metal salt solution and then forwarding the resulting aqueous acidified chlorate ion-containing solution to said reaction zone to provide chlorate ion and hydrogen ion reactants to said aqueous acid chlorine dioxide-generating reaction medium, and recovering from said reaction zone an alkali metal sulfate in the solid phase, wherein the electrochemical steps are conducted at current efficiencies of 70% or greater.