N-P PRODUCTS

DAP and MAP

Diammonium Phosphate and Monoammonium Phosphate

Ammonium Phosphates, N-P grades, are the reaction products of varying degrees of neutralization of phosphoric acid with anhydrous ammonia.

The different products that are marketed worldwide vary widely in nitrogen and P2O5 guarantees and are produced by various processes and modifications. However, the principal grades produced in Florida and North Carolina are made from "wet-process" phosphoric acid and are 18-46-0 (diammonium phosphate) and grades 10-50-0, 11-52-0 and 12-52-0 (monoammonium phosphate).

Although manufacturing processes and techniques differ among the various are plants, the first step in ammonium phosphate production is the partial neutralization of the the phosphoric acid with anhydrous ammonia in a reaction vessel. Water vapor is evolved from the heat of reaction of the acid and ammonia. The partially neutralized slurry is then pumped to an ammoniator granulator where it is distributed over the rolling bed of recycled fines from the product screening operations and sufficient anhydrous ammonia is added to produce the desired product grade.

The product from the granulator discharge into a rotary dryer where the moisture content is reduced to the desired level. The dryer discharge is then fed to the screening section to separate the product size from the undersize and oversize materials. The oversize, after being crushed, is either rescreened or recycled together with the undersize fractions back to the ammoniator granulator.

The on-size products from the screening operation is passed through a rotary cooler and then conveyed to storage. The ammonium phosphate products are shipped by rail and are exported through the Florida and North Carolina ports for water shipment. These products provide the advantages of two nutrient content, high water solubility, high analysis, good physical characteristics and lower transportation and handling cost per unit of plant nutrient.