There are three ways to produce caustic soda in industry
Causticization method: Soda ash and lime are made into soda ash solution and lime into lime milk respectively, and the causticizing reaction is carried out at 99 to 10 degrees Celsius. The causticizing solution is clarified, evaporated and concentrated to more than 40%, and the obtained liquid caustic soda.
Diaphragm electrolysis method: add soda ash, caustic soda, and barium chloride refined preparations to remove impurities such as calcium, magnesium, and sulfate ions after the original salinized salt, and then add sodium polyacrylate or causticized bran to the clarification tank to accelerate precipitation. After sand filtration, add hydrochloric acid to neutralize. After preheating, the brine is sent to electrolysis. The electrolyte is preheated, evaporated, separated from salt, and cooled to obtain liquid caustic soda.
3. Ion-exchange membrane method: After the original salinization salt is refined according to the traditional method, the primary refined brine is filtered through a microporous sintered carbon tubular filter, and then secondary refined through a chelating ion-exchange resin tower , so that the calcium and magnesium content in the brine is reduced to below 0.002%, and the secondary refined brine is electrolyzed to generate chlorine gas in the anode chamber, which can be directly used as a liquid caustic soda product, or can be further boiled to obtain a solid caustic soda product.
