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

FIELD: production of alkali metal phosphate, more particularly monosubstituted dihydrate sodium phosphate in food industry, and impregnation of fabrics to make them fireproof. SUBSTANCE: method comprises neutralization of phosphoric acid with sodium hydroxide at original sodium hydroxide to phosphoric acid molar ratio of 0.95-1.0:1, evaporation and filtration to separate impurities, maintenance of saturated solution for 100-300 minutes prior to crystallization followed by filtration and crystallization of said solution by cooling to 5-19 C. Commercial product is separated from mother liquor. EFFECT: higher quality of commercial sodium phosphate and greater process efficiency due to reduced content of impurities in final product and preparation of large transparent crystals of monosubstituted dihydrate sodium phosphate of rhombic shape. 1 tbl