Israelian phosphate rock was treated with H(2)SO(4) (conc. 76% by mass) at 90 degrees C for 60 min to decomp. the rock-contained fluoroapatite to sol. Ca(H(2)PO(4))(2)center dot H(2)O. The H(2)SO(4) amt. was lower than the stechiometric one. The content of the citric acid-sot. P compds. increased up to 11% by mass with decreasing the H(2)SO(4) amt. and did not depend on the reaction time.