Eka Nobel

Eka Nobel Ab

John M Gray

John R Winters

Joel D Tenney

Timothy M Garrison

Harold M Schubert

David C Lovetro

Matthew R Lauber

The invention relates to a process of producing chlorine dioxide comprising the steps: Providing a reactor with an aqueous acidic reaction medium containing alkali metal chlorate and sulfate; reducing chlorate ions in said reaction medium to form chlorine dioxide; maintaining the reaction medium at subatmospheric pressure sufficient to evaporate water and precipitate alkali metal sulfate; withdrawing chlorine dioxide and evaporated water from the reactor; withdrawing reaction medium containing solid alkali metal sulfate from the reactor and separating the solid material from said reaction medium; transferring reaction medium substantially free from solid alkali metal sulfate to an electrochemical cell in which the acidity of said reaction medium is increased and the content of alkali metal ions is decreased; recycling electrochemically acidified reaction medium to the reactor for producing chlorine dioxide; and adding make up alkali metal chlorate and sulfuric acid.

Process of producing chlorine dioxide

A process for the production of chlorine dioxide by reacting at least one of chloric acid and an alkali metal chlorate, and hydrogen peroxide as the reducing agent in such proportions that chlorine dioxide is produced in a reaction medium. A mixture comprising chlorine dioxide and oxygen is withdrawn from the reaction medium. Urea and/or one or more phosphonic acid based complexing agents are added to the reaction medium. The stabilizer is added in an amount of 0.01-5 weight % and serves to increase the reaction rate.

Process for the production of chlorine dioxide

The invention relates to a method of producing chlorine dioxide, which method comprises reacting chloric acid with hydrogen peroxide as a reducing agent in such proportions that chlorine dioxide is produced.

Method of producing chlorine dioxide

Waste water effluent streams are treated with hydrogen peroxide and ultraviolet radiation. Hydroxyl ions formed by action of UV on H.sub.2 O.sub.2 reduces BOD, COD, AOX and color in effluent. In the case of pulp mill effluent, some or all of the effluent can then be recycled to the pulp mill.

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Roswell, GA, United States of America

John M Gray