The method we use in Niltech Corporation is to use hydrogen peroxide based on Degussa method. All the process parameters are proprietary modified in a way that in addition to economic advantages, a high quality product is achieved which is comparable with today’s world standards.
Overall reaction is as follows:
2 ClO2 + 2 NaOH + H2O2 → 2 NaClO2 + 2 H2O + O2
In this method, production of oxygen gas beside chlorine dioxide brings up safety challenges which can be managed with complete understanding and accurate control of the parameters.
In industrial scales, the chlorine dioxide, required to produce sodium chloride, is produced from decomposition of sodium chlorate (NaClO3) in the vicinity of a strong acid and an oxidizer regent. The strong acid can be hydrochloric acid or sulfuric acid and the oxidizer regent is usually sulfur dioxide.
Its overall reaction is as follows:
2 NaClO3 + H2SO4 + SO2 → 2 ClO2 + 2 NaHSO4
After separation of sulfate salt cake, the produced chlorine dioxide in this reaction is diluted with air and then changed into sodium chlorite in absorber column based on Degussa method.
The final product is sodium chlorite solution with a concentration of 35 to 40 percent which is then shifted to the required concentration and presented based on consumer’s need and the installed injection generator package in consumer’s unit.
However, chlorine dioxide production and injection generators may need different concentrations of sodium chlorite, based on their construction technology. Hence, Niltech Corporation presents any standardized concentration of sodium chlorite based on consumers’ need.
The important point to be considered in the matter of sodium chlorite’s concentration is that its measurement and standardization needs to be extremely accurate. That’s due to the fact that deviation from the required concentration in the time of chlorine dioxide production and usage can cause problems. For instance, if the concentration is more than required, sodium chlorite won’t react and stay in water which is one the important DBPs in using chlorine dioxide. Moreover, if the concentration is less than required, the amount of produced chlorine dioxide will be less than required and disinfection process will be impaired.
If capacity of the production unit is more than 20 thousand tons per year, it will also be economically affordable to also produce sodium chlorate as a consumable.
The common method to produce sodium chlorate is to electrolyze sodium chloride. Cost of electricity and availability of sodium chloride are both affecting parameters on the economy of this process. Since our country owns sodium chloride mine with great and unique quality and also regarding the cost of electricity, which is less than the rest of the world, sodium chlorate can be one of the relative advantages of Iran in the world market of sodium chlorate and sodium chlorite.