Patent ID: 6620395
Filing Date: 2003-09-16
Classification: C01B,C01F,C04B

Abstract:
A process for recovering phosphoric acid from phospho gypsum produced as a by-product in a phosphoric acid production process and having water soluble P2O5 bound in the crystal lattice thereof, the process comprising:a) forming a suspension of phospho gypsum in an aqueous medium; b) subjecting the suspension to ultrasonic waves under conditions suitable to shatter the phospho gypsum crystal lattice releasing the bound water soluble P2O5 into the aqueous medium to produce phosphoric acid and a depleted phospho gypsum; c) separating the phosphoric acid from the depleted phospho gypsum and recovering the separated phosphoric acid; and d) optionally further treating the depleted phospho gypsum in a step to further reduce the level of any remaining water soluble P2O5 present in the depleted phospho gypsum, wherein the level of the water soluble P2O5 in the depleted phospho gypsum is reduced to about 0.01% by weight.