Multi-stage process of producing di-ammonium phosphate

Claim 1

AN IMPROVED MULTI-STAGE ACCRETION PROCESS OF PRODUCING DRIED ROUNDED SOLID PARTICELS COATED WITH ACCRETIONS OF DI-AMMONIUM PHOSPHATE GRANULATED FERTILIZER WITH A HIGH RATIO OF N:P2O5 HIGHER THAN 1:3 AND WITH THE VALUE OF PH INCREASING FROM ONE STAGE TO ANOTHER UP TO AT LESAT AS HIGH AS ABOUT 6.9 TO ABOUT 8.35 WHICH COMPRISES REACTING AMMONIA AND WEAK PHOSPHORIC-ACID-CONTAINING MATERIAL, CONTAINING AS LOW AS ABOUT 28% TO ABOUT 35% P2O5 IN A FIRST STAGE OF OPERATION IN AN AMOUNT SUFFICIENT TO OBTAIN A PH OF ABOUT 6.3 TO ABOUT 6.4 TO PRODUCE A LIQUID MASS CONTAINING A SUBSTANTIAL AMOUNT OF DI-AMMONIUM PHOSPHATE, FLOWING SAID LIQUID MASS TO A SECOND STAGE OF OPERATION; SUBJECTING SAID MASS TO FURTHER TREATMENT WITH SUFFICIENT AMMONIA IN SAID SECOND STAGE TO RAISE THE PH OF THE LIQUID MASS IN THE SECOND STAGE TO AT LEAST ABOUT 6.9 AND UP TO AT LEAST AS HIGH AS ABOUT 8.35 TO PRODUCE DI-AMMONIUM PHOSPHATE WITH AN N:P2O5 RATION IN A SLURRY HIGHER THAN 1:3; SUPPLYING SAID AMMONIA IN AN EXCESSIVE AMOUNT TO PROVIDE AN EXCESS OF 75% TO 150% OF AMMONIA OVER THE STOICHIOMETRIC AMOUNT REQUIRED IN SAID SECOND STAGE OF OPERATION TO PRODUCE DI-AMMONIUM PHOSPHATE IN A SLURRY; EXHAUSTING VAPORS AND GASES INCLUDING UNUSED EXCESS AMMONIA FROM SAID SECOND STAGE; SCRUBBING SAID VAPORS AND GASES INCLUDING SAID EXCESS AMMONIA WITH WEAK PHOSPHORIC ACID CONTAINING ABOUT 28% TO ABOUT 35% P2O5 TO ABSORB SAID AMMONIA AND TO PROVIDE WEAK PHOSPHORIC-ACID-CONTAINING MATERIAL CONTAINING ABOUT 28% TO ABOUT 35% P2O5 FOR THE FIRST STAGE OF OPERATION; TRANSFERRING SAID DIAMMONIUM PHOSPHATE SLURRY PRODUCED IN SAID SECOND STAGE CONTAINING A HIGH RATE OF N:P2O5 OF AT LEAST 1:3 AND DISTRIBUTING SAID SLURRY OVER AN ELONGATED BED OF ROLLING PARTICLES OF GRANULATED DI-AMMONIUM PHOSPHATE HAVING AN N:P2O5 RATIO OF AT LEAST 1:3 AT A TEMPERATURE NOT EXCEEDING ABOUT 210*F. TO PRODUCE DRIED ROUNDED SOLID DI-AMMONIUM PHOSPHATE PARTICLES COATED WITH ACCRETIONS OF DIAMMONIUM PHOSPHATE; AND RECOVERING SAID DRIED PARTICLES AS A FINISHED PRODUCT CONSTITUTED OF ROUNDED GRANULATED PARTICLES OF DI-AMMONIUM PHOSPHATE HAVING A N:P2O5 RATIO HIGHER THAN 1:3.