METHOD OF PREPARING SODIUM PYRO PHOSPHATE Russian patent published in 2001 - IPC

FIELD: production of alkali metal, more particularly pyro sodium phosphate (tetra sodium pyrophosphate) in food industry, and reagent for organic synthesis. SUBSTANCE: method comprises neutralizing phosphoric acid with sodium hydroxide to pH of 9.1-9.5, followed by filtration to separate impurities by dehydration of the resulting solution by drying in spraying drier at 280-350 C, dissolution of powder-like pyrophosphate, maintaining saturated solution for 100-130 minutes prior to crystallization, crystallization of pyro decahydrate sodium phosphate by cooling to 16-25 C and separating commercial product from method liquor. EFFECT: higher quality of commercial sodium pyrophosphate and greater process efficiency due to lower content of impurities in final product and preparation of large transparent crystals of sodium pyrophosphate. 1 ex, 1 tbl