PROCESS FOR PREPARATION MONOBASIC SODIUM PHOSPHATE SOLUTION Russian patent published in 1994 - IPC

FIELD: inorganic chemistry. SUBSTANCE: solution of monobasic sodium phosphate is prepared by extracting phosphoric acid with organic solvents from solution of wet-process phosphoric acid followed by secondary countercurrent extraction of the resulting phosphoric acid from organic solvents using solution of mono- and dibasic sodium phosphates at the total P₂O₅ content of 8.5-17.0. The countercurrent re-extraction of phosphoric acid is carried out for 2-5 stage-process in organic-to-aqueous phase ratio of 2-7: 1, with dibasic sodium phosphate content in mixture being 12.6-67.8 % based on stoichiometry to neutralize phosphoric acid. The resulting phosphoric acid solution of monobasic sodium phosphate is divided into two portion one of which is recovered as the end product, and the other is treated with sodium carbonate and passed through the stage of re-extraction. EFFECT: allows concentration of the product to increase to 42 % P₂O₅. 2 cl, 1 tbl