Erco Industries Limited

Norman W Meyers

Maurice C Fredette

W Howard Rapson

Chlorine dioxide is produced in a continuous process by reaction of sodium chlorate and hydrochloric acid. The reaction medium is maintained at its boiling point under subatmospheric pressure and the resulting steam is used to dilute the chlorine dioxide and chlorine and remove the same from the reaction zone. Sodium chloride is deposited from the reaction medium in the reaction zone. The mole ratio of chlorate to chloride in the reaction medium, and the temperature of the reaction medium are controlled within narrow limits to provide high efficiency of production of chlorine dioxide.

Production of chlorine dioxide at high efficiency

An electrode having a conductive platinum alloy coating and which has deteriorated in use in an electrolytic chlorate cell is heat treated at elevated temperatures of above 300.degree. C to regenerate the coating. The regeneration of the coating is exhibited by a decreased oxygen concentration in the cell off gases after the heat treatment. Further improvement in cell characteristics in severely deteriorated anodes may be achieved by coating the anode surface with a platinum group metal prior to or during the heat treatment.

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Islington, Canada

Norman W Meyers