As a quality improver, it can improve the complexed metal ions, pH value, and ionic strength of food, thereby improving the binding force and water holding capacity of food. Used as boiler water softener, flame retardant for fabric, wood and paper, glaze and welding flux. Used in the production of detergents, cleaning agents for printing plates and mordants for dyeing. In the printing and dyeing industry, it is used as a stabilizer for hydrogen peroxide bleaching, and a filler for rayon Chemicalbook (to enhance the strength and elasticity of silk). It is the raw material for the manufacture of sodium pyrophosphate and other phosphates, and it is also the culture agent for monosodium glutamate, erythromycin, penicillin, streptomycin and sewage biochemical treatment products. Also used for electroplating and tanning.