Process for preparing liquid fertilizers
AssigneeMontecatini Edison S.p.A.
InventorsAlessandro Frangioni, Giovanni Venturino, Giorgio Morandi, Adriano Del Vesco
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Abstract
Improved stable suspension liquid fertilizers based on ammonia and phosphoric acid obtained by the wet method, and combining both a high content of fertilizing elements and a long storage life are prepared by ammoniating the phosphoric acid with gaseous ammonia in two steps at a temperature of from 90.degree.C to 120.degree.C until a pH of between 6 and 8 is attained, rapidly cooling the resulting ammonium phosphate suspension to a temperature of from 0.degree.C to 35.degree.C, and during the cooling adding a suspending agent to the suspension while maintaining the suspension under stirring.
Claims8
A continuous process for the preparation of suspension liquid fertilizers starting from ammonia and phosphoric acid having a P.sub.2 O.sub.5 concentration not higher than 36% by weight obtained by the wet method, and which fertilizers contain ammonium phosphate in suspension, said process comprising the following steps:
- 1. ammoniating the phosphoric acid with gaseous ammonia until a pH comprised between 4 and 5 is attained, said ammoniating step being carried out at temperatures comprised between 105.degree.C and the boiling temperature of the resulting suspension and for a time of from 30 to 90 minutes;
- 2. continuing the ammoniation with gaseous ammonia until the pH of the suspension is comprised between 6 and 8, this second ammoniation step carried out at temperatures comprised between 105.degree.C and the boiling temperature of the suspension;
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- 3. rapidly cooling the ammonium phosphate suspension thus obtained to a temperature comprised between 0.degree.C and 35.degree.C and during the cooling adding a suspending agent while maintaining the suspension under stirring.
Dependencies are inferred from the claim text.