DAP is the most widely used phosphate fertilizer. It has an analysis of 18-46-0. For most soils with pH less than 7.5, the agronomic effects of diammonium and monoammonium phosphates are equal. Some research has shown MAP to be more effective on calcareous soils where pH exceeds 7.5. DAP has a high ammonium content and can cause germination injury if used in direct contact with seed. DAP is manufactured by reacting phosphoric acid and ammonia. It contains two ammonia molecules. In alkaline soil conditions, one of the ammonia molecules in DAP will revert to ammonia. DAP is alkaline with a high pH, exceeding 7.5. DAP is excellent for low pH or alkaline soils. The most common delivery modes for DAP are truck, railcar, barge or vessel. The mode is determined by customer needs and geography.



the following sections are key to control hazards


Phosphate as P2O5
Nitrogen as N
Fluorides as F

45.5 – 46.3 %
17.5 – 18.3 %
1 – 2 %
2 – 4 %




Move victim away from exposure and into fresh
air. Flush eyes with plenty of clean water for at
least 15 minutes. If symptoms persist, seek
medical attention.


Wash contaminated area thoroughly with mild
soap and water. If chemical or solution soaks
through clothing, remove clothing and wash
contaminated skin. If irritation develops and
persists after washing, seek medical attention.


If person is conscience, immediately give water
or milk. Do not induce vomiting. Seek medical
attention. If person is unconscious, do not give
anything by mouth.


If respiratory symptoms develop, move victim
away from source of exposure and into fresh air.
If symptoms persist, seek medical attention

If person has been exposed to concentrated decomposition products, treat symptomatically and watch for delayed symptoms of pulmonary edema.

Di ammonium phosphates preparation

Two basic mixer designs are used by ammoniation-granulation plants: the pugmill ammoniator and the rotary drum ammoniator. Approximately 95 percent of ammoniationgranulation plants in the United States use a rotary drum mixer developed and patented by the Tennessee Valley Authority (TVA). The basic rotary drum ammoniator-granulator consists of a slightly inclined open-end rotary cylinder with retaining rings at each end, and a scrapper or cutter mounted inside the drum shell. A rolling bed of recycled solids is maintained in the unit. Ammonia-rich off gases pass through a wet scrubber before exhausting to the atmosphere. Primary scrubbers use raw materials mixed with acids (such as scrubbing liquor), and secondary scrubbers use gypsum pond water. In the TVA process, phosphoric acid is mixed in an acid surge tank with 93 percent sulfuric acid (H2SO4), which is used for product analysis control, and with recycled acid from wet scrubbers. (A schematic diagram of the ammonium phosphate process flow diagram is shown in Mixed acids are then partially neutralized with liquid or gaseous anhydrous ammonia in a brick lined acid reactor. All of the phosphoric acid and approximately 70 percent of the ammonia
are introduced into this vessel. A slurry of ammonium phosphate and 22 percent water are produced and sent through steam-traced lines to the ammoniator-granulator. Slurry from the reactor is distributed on the bed, the remaining ammonia (approximately 30 percent) is sparged underneath. Granulation, by agglomeration and by coating particulate with slurry, takes place in the rotating drum and is completed in the dryer. Ammonia-rich offgases pass through a wet scrubber before exhausting to the atmosphere. Primary scrubbers use raw materials mixed with acid (such as scrubbing liquor), and secondary scrubbers use pond water. Moist ammonium phosphate granules are transferred to a rotary concurrent dryer and then to a cooler. Before being exhausted to the atmosphere, these offgases pass through cyclones and wet scrubbers. Cooled granules pass to a double-deck screen, in which oversize and undersize particles are separated from product particles. The product ranges in granule size from 1 to 4 millimeters (mm). The
oversized granules are crushed, mixed with the undersized, and recycled back to the ammoniatorgranulator.


Diammonium phosphate (DAP) (chemical formula (NH4)2HPO4 ) is one of a series of watersoluble
ammonium phosphate salts which can be produced when ammonia reacts with phosphoric acid. DAP is used as a fertilizer and a fire retardant. When applied as plant food, it temporarily increases the soil pH (more basic), but over a long term the treated ground becomes more acidic than before upon nitrification of the ammonium. It is incompatible with alkaline chemicals because its ammonium ion is more likely to convert to ammonia in a high-pH environment.DAP is sometimes used as a yeast nutrient in winemaking and brewing mead, and is an additive in some brands of cigarettes purportedly as a nicotine enhancer.

Phosphorus as a Pollutant
Because of its rapid fixation, phosphorus is seldom leached from soils. However, P can still become a pollutant to our waters especially when P levels exceed 15 ppm. Phosphorus becomes an environmental problem when soil particles containing P erode off site or run off contains organic P. Excessive phosphorus from runoff and erosion can fertilize surface waters. In this process, called eutrophication, microscopic floating plants, known as algae, multiply rapidly when fertilized by phosphorus.
These algae cloud the water making it difficult for larger submerged aquatic vegetation (SAV) to get enough light. Excessive plant growth in water bodies may also lead to the death of fish and other aquatic animals from lack of oxygen in the water. (Oxygen is used by plants for respiration and by micro-organisms in breaking down plants after they die.) Phosphorus pollution comes from many sources in urban areas, mainly sewage treatment plants, storm sewers, and industrial sources. Most of these are point sources (i.e. easy to locate). In rural areas, the sources are sewage treatments from small towns, improper septic systems, storm sewers, manure runoff, nutrient runoff, milkhouse wastes, and eroded soil. Most of these are nonpoint sources (i.e. harder to pinpoint). Phosphorus from farmland has three sources: the farmstead, pastures near watercourses, and cropland. Recently the state of Minnesota has passed legislation to prevent the sale of P containing lawn fertilizers for the Twin Cities Metro area. Most soils are already very high in P and additional P in fertilizer would contribute to phosphorus pollution. Soil Scientists are also doing research to develope a Phosphorus Index (P Index) that can identify farm fields that are a potential source of phosphorus (P) pollution of surface waters. Using the P Index can help a farmer identify fields and management practices that have the greatest potential to pollute bodies of water with phosphorus. The P index can help land users assess management strategies to minimize P loss from agricultural areas.


It is used as a fertilizer . when applied as plant food , it temporarily increases pH of Soil.
It used as a fire retardant.
It is also used as a yeast nutrient.

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