Preparation of mixed fertilizers

Claim 1

A PROCESS FOR THE CONTINUOUS PRODUCTION OF A DRY, GRANULAR FERTILIZER CONTAINING APPROXIMATELY 26-27 WEIGHT PERCENT NITROGEN AND 14 PERCENT PHOSPHORUS, AS P2O5, USING ONLY LIQUID REACTANTS WHICH COMPRISES BRINGING TOGETHER IN AN AGITATED REACTION ZONE PROPER AMOUNTS OF A NITROGENCONTAINING SOLUTION IN THE FORM OF A SOLUTION OF AMMONIUM NITRATE AND ANHYDROUS AMMONIA IN WATER AND CONCENTRATED SULFURIC ACID AT LEAST ABOUT 90 PERCENT BY WEIGHT AND CONCENTRATED PHOSPHORUS ACID HAVING AT LEAST 45 PERCENT BY WEIGHT P2O5 IN THE PRESENCE OF PRE-FORMED SOLID SUBDIVIDED FERTILIZER PRODUCT HAVING SUBSTANTIALLY THE AFORESAID COMPOSITION, MAINTAINING THE REACTION ZONE AT A TEMPERATURE IN THE APPROXIMATE RANGE OF 195-230*F., MAINTAINING A SUFFICIENT BODY OF SOLID PRODUCT IN THE REACTION ZONE TO ENSURE DISCHARGE OF DRY, SOLID GRANULAR PRODUCT THEREFROM, SEPARATING FROM GRANULAR PRODUCT THUS OBTAINED A DESIRED FIRST PORTION OF ON-SIZE PRODUCT CONSISTING ESSENTIALLY OF DRY, GRANULAR FERTILIZER CONTAINING APPROXIMATELY 26-27 WEIGHT PERCENT NITROGEN AND 14 PERCENT PHOSPHORUS, AS P2O5, AND A SECOND PORTION OF PRODUCT COMPOSED OF MATERIAL HAVING A SIZE NOT APPRECIABLY LARGER THAN ON-SIZE PRODUCT AND CONTAINING A SUBSTANTIAL PORTION OF SMALLER THAN ON-SIZE MATERIAL, RECYCLING SAID SECOND PORTION OF SOLID GRANULAR PRODUCT TO SAID ZONE, ADJUSTING THE RATIO OF THE RECYCLED PRODUCT TO LIQUID REACTANTS FED TO SAID REACTION ZONE, ON A WEIGHT BASIS, TO A VALUE OF AT LEAST ABOUT 2:1 AND WHENEVER THE SAID RATIO IS LESS THAN ABOUT 3:1 YET NOT LESS THAN ABOUT 2:1, MAINTAINING A RATIO BY WEIGHT OF SAID RECYCLED PRODUCT TO TOTAL WEIGHT OF THE ACIDS ABOVE ABOUT 4:5:1.