METHOD OF DICALCIUM PHOSPHATE PRODUCING Russian patent published in 1994 - IPC

FIELD: chemical technology. SUBSTANCE: dicalcium phosphate is prepared by treatment of nitratephosphate solution with ammonium at the two stages. At the first stage pH is brought about to 2.5-4.0, at the second one - up to 5.5-7.0. At the every stage impurity contaminant is separated, and purified solution is treated with calcium nitrate, and product is precipitated. Method ensures to diminish impurity contents, at % with relative to P₂O₅: fluorine is up to (24-26) x (24-66)·10^-4, iron is up to (5.5-12.0) x (5,5-12,0)·10-4, aluminium is up to (6.9-19.0) x (6,9-19,0)·10^-3; pH value of the aqueous suspension is 6.9-7.2. EFFECT: enhanced quality of product. 2 cl, 1 tbl