Acidity controlled chlorine di:oxide prodn. - by redn. of sodium chlorate with sulpohur di:oxide, sodium chloride, methanol etc.

摘要

Chlorine dioxide is generated by redn. of a chlorate soln. in the presence of hydrogen ions at a pH value which is less than 7, using one or more redn. media and cpds. contg. sulphur, in the form of a redn. medium and/or an acid. The hydrogen ion content or acidity with chlorine dioxide generation is wholly or partially maintained with the aid of acid, obtd. by electrolysis of a soln. of sodium sulphate (Na2SO4 or Na3H(SO4)2), produced by crystallisation and re-dissolving of the sodium sulphate formed with chlorine dioxide generation, the electrolysis being limited so that a part of the sodium sulphate is recirculated for chlorine dioxide generation together with the formed acid. The electrolysis cell used is equipped with an iron cathode, a platinated titanium electrode and a unipolar cation-selective membrane. At the cathode, hydrogen gas is developed and at the anode oxygen gas is formed. To the anode space is fed through a conduit a sodium sulphate soln. and through a further conduit the formed acid is fed away. To the cathode space is fed through a conduit clean water and through a further conduit formed sodium hydroxide is fed away.