GB1149924A - Improvements in or relating to the production of urea phosphate - Google Patents

Abstract

1,149,924. Urea phosphate. POWER-GAS CORP. Ltd. 24 Oct., 1967 [2 Nov., 1966], No. 49115/66. Heading C2C. A process for the continuous production of urea phosphate comprises the steps of forming an aqueous feed solution of phosphoric acid and urea, heating said solution and evaporating water therefrom, with or without subsequent cooling, to yield a supersaturated solution of urea phosphate, forming a suspension of forming and growing crystals of urea phosphate in a mother liquor in which the weight ratio H 3 PO 4 to CO(NH 2 ) 2 on a water-free basis is held between pre-determined limits depending on the mother liquor temperature, contacting said supersaturated solution with said suspension, withdrawing grown crystals of urea phosphate from the contacted solution and suspension, withdrawing mother liquor from the contacted solution and suspension, recycling said mother liquor and adding phosphoric acid, urea and water thereto to form the aqueous feed solution so that in the mother liquor after crystallization the weight ratio H 3 PO 4 to CO(NH 2 ) 2 on a water-free basis is maintained within the said limits. The concentrated feed solution may be cooled by indirect heat exchange, subsequent to the evaporation of water to yield the supersaturated solution of urea phosphate, or if the concentrated feed solution is not to be cooled the evaporation of water may be carried out under vacuum by flashing off steam from the heated solution. The urea phosphate produced may be worked up using conventional procedures, suitable forms of apparatus being described for carrying out the continuous process.