It is used to make special soap, insecticide, hard water softening, beet sugar refining, boiler descaling, glass lubrication, etc. it is also used to prepare organic synthesis and barium salt; In chemical experiments, in addition to being used as a reagent, it can also be used as an alkaline desiccant because of its strong hygroscopicity. The sectors that use caustic soda most are chemical manufacturing, followed by papermaking, aluminum smelting, tungsten smelting, rayon, artificial cotton and soap manufacturing. In addition, in the production of dyes, plastics, chemicals and organic intermediates, the regeneration of old rubber, the electrolysis of metal sodium and water, and the production of inorganic salts, a large amount of caustic soda is also used in the production of borax, chromate, manganate, phosphate, etc.