Process for preparing chlorine dioxide

Abstract

The present invention belongs to be field of environment protection and water treating technology. Sodium chlorate and hydrochloric acid are made to react to prepare chlorine dioxide, and the reaction conditions include sodium chlorate concentration 45-60%, hydrochloric acid concentration 31-36%, reaction temperature 60-70 deg.C, reaction pressure lower than 200 mmHg, the hydrochloric acid / sodium chlorate molar ratio 2.8-3.5 and reaction time 10-30 min. The present invention has a sodium chlorate converting ratio as high as 93-99% and the very low unreacted sodium chlorate content makes the chlorine dioxide product suitable for use in drinking water sterilization.

Description

technical field [0001] The invention relates to a method for preparing chlorine dioxide, belonging to the technical fields of environmental protection and water treatment. Background technique [0002] Chlorine dioxide is used for disinfection of water in the fields of environmental protection and water treatment. The existing methods for preparing chlorine dioxide have two categories: sodium chlorate method and sodium chlorite method. The sodium chlorite method uses sodium chlorite as a raw material and reacts with hydrochloric acid, sulfuric acid or chlorine to produce chlorine dioxide. The disadvantage of this method is that the cost of sodium chlorite is high, so the cost of chlorine dioxide produced is very expensive; The sodium chlorate method uses sodium chlorate as a raw material, and reacts with hydrochloric acid or sulfuric acid plus a reducing agent to produce chlorine dioxide. Because the cost of sodium chlorate is much lower than that of sodium chlorite, the co...

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Problems solved by technology

The reaction conditions of the existing chlorine dioxide equipment utilizing this reaction are not ideal enough, the raw material concentration is low, the concentration of sodium chlorate is 30%, the reaction negative pressure is insufficient, the reaction temperature is low (normal temperature~65 ℃), and the conversion rate of sodium chlorate is only 40%. ~83%, thus causing waste of raw materials, and increased the cost of chlorine dioxide, and adding unreacted sodium chlorate into the sterilized water will bring other problems such as sanitation and safety, so in fact there is no such thing at present Method for producing chlorine dioxide by sodium chlorate method for disinfection of drinking water