Patent ID: 6241796
Filing Date: 2001-06-05
Classification: C05B

Abstract:
A process for enhancing the ammoniacal nitrogen concentration of DAP, comprising subjecting said DAP, which is in finely divided form and which due to the impurities contained in the phosphoric acid used to produce it, contains less than 18.0 percent by weight of ammoniacal nitrogen, but which contains sufficient excess phosphate to compensate for the dilution effect that would be created by the quantity of ammonia necessary to raise the ammoniacal nitrogen concentration to at least 18.0 percent by weight and still contain at least 46.0 percent by weight of phosphate, as P.sub.2 O.sub.5, to anhydrous gaseous ammonia which is at super atmospheric pressure and which is at a temperature sufficient to maintain said ammonia in the gaseous state, such that a quantity of triammonium phosphate (TAP) is incorporated into the DAP that is sufficient to raise the total ammoniacal nitrogen concentration of the DAP to at least 18.0 percent by weight, the quantity of triammonium phosphate formed and the increase in the ammoniacal concentration being a function of the absolute ammonia pressure, the initial moisture content of said DAP and the contact time of the gaseous ammonia with said DAP.