Tuesday,Dec 24, 2024 
（1）Production process principle
The production process of sodium chlorite usually adopts electrolytic method and reduction method. The reduction method has high utilization rate of sodium chlorite, simple production process, less equipment investment, strong stability, convenient operation and easy control advantages. Therefore, the reduction method is adopted in this project.
The reduction method production process can be divided into two steps: the first step uses hydrogen peroxide as a reducing agent to produce chlorine dioxide, which has the advantages of low impurity of chlorine content, fast generation speed, and high target conversion rate of sodium chlorate to chlorine dioxide. Due to the high purity of the generated chlorine dioxide and low impurity content, the obtained sodium chlorite has a high purity, which can reach more than 95%. Meanwhile, the post-treatment process of the corresponding semi-finished sodium chlorite solution is reduced.
The reaction equation of the reduction method is as follows：
2NaClO3 + H2O2 + 2H2SO4 → 2ClO2 + 2NaHSO4 +2H2O + O2↑
2ClO2 + 2NaOH + H2O2 → 2NaClO2 +2H2O + O2↑
Remark：Products under this process are ClO2、NaHSO4、NaClO2、H2O、O2，no contaminants are produced.
（2）Brief description of production process
The first stage: reaction stage
The solid sodium chlorate and water are put into the dissolving tank according to a certain ratio, the solid sodium chlorate is completely dissolved by stirring to prepare sodium chlorate solution. Keep the temperature of the solution at 50°C and use it as a raw material for reaction.
Adding sodium chlorate solution, sulfuric acid solution and hydrogen peroxide to the main generator (closed negative pressure) in a fixed ratio. Sodium chlorate is reduced with hydrogen peroxide to generate chlorine dioxide gas under acidic state, temperature 55℃, and pressure -100~-150mmH2O,chlorine dioxide gas is pumped into the absorption tank by the jet pump through the pipeline. At this stage, in order to make the chemical reaction completely, one sub-generator is also installed to make reaction slowly and incompletely reacted solution is carried out in the sub-generator. Hydrogen peroxide should also be added in the sub-generator to prevent the reduction of chlorine dioxide gas to be sodium chlorate, and prevent the unreacted sodium chlorate from being discharged with the remaining liquid resulting in waste of raw materials. This process produces oxygen and chlorine dioxide gas through the pipeline to enter the absorption, the tank and tail liquid enter the temporary storage tank for further recycling.
The second stage: absorption stage
The chlorine dioxide gas generated in the generation stage is sent to the absorption tank, where it comes into contact with lye and hydrogen peroxide is used as a reducing agent to absorb chlorine dioxide gas. After the absorption operation starts, the lye is pumped into the circulation by an absorption pump, it enters the absorption tank to reciprocate and absorb after reacting with the chlorine dioxide. The semi-finished product overflows into the semi-finished liquid storage tank, and then enters the next process. The absorption tank needs to periodically discharge the oxygen in the tank. This process will take out a small amount of chlorine and sulfuric acid mist, the acid gas will be removed by the installed acid mist purification tower.
The third stage: concentration, cooling & crystallization stage
The solution after absorbing chlorine dioxide gas in the absorption tank is the mixed solution of sodium chlorite and excessive sodium hydroxide, which is evaporated and concentrated. There will be sodium chlorite crystals after cooling, which is dehydrated by a centrifuge to separate alkaline sodium chlorite solution is recycled, then the dehydrated sodium chlorite solid is dried. The cooling process uses indirect cooling circulating water. The separated sodium chlorite enters the fluidized drying bed for drying. The heat source comes from hot steam. During the drying process, sodium chlorite dust is generated where is installed induced draft fan and dust removal bag at the end that can ensure the maximum efficiency of sodium chlorite recycle and reduce the discharge of sodium chlorite particles.
The fourth stage: by-product reaction stage
The waste liquid in the first stage reactor enters the concentration process. The semi-finished product of sodium bisulfate is produced after concentration, then it enters the cooling and crystallization process to form a semi-finished solid sodium bisulfate. The crystallized semi-finished product is centrifuged by a centrifuge. The centrifuged solid enters the packaging process, it is the final solid product, which will be packaged and sold to the market. Partial solution after centrifugation directly enters the production process of liquid sodium bisulfate, then finished product is packed in cans to sell to the market. Partial waste liquid before centrifugation is temporarily stored in the intermediate tank and then reused in the generator.
The process is safe and environmentally friendly, and there is no national crucial monitoring pollutant generation, no sulfur-containing, nitrogen-containing, or carbon-containing waste. The chlorine atoms in the process are also converted into NaClO2 at a very high conversion rate.