ammoniumfosfat

Ammoniumfosfat, commonly called ammonium phosphate, refers to a family of inorganic salts derived from phosphoric acid and ammonia. The two principal members are monoammonium phosphate (MAP, NH4H2PO4) and diammonium phosphate (DAP, (NH4)2HPO4). These are white to off-white crystalline solids that dissolve readily in water and are hygroscopic.

Production and forms: MAP forms from the reaction of phosphoric acid with one equivalent of ammonia (H3PO4 + NH3 → NH4H2PO4). DAP forms with two equivalents of ammonia (H3PO4 + 2 NH3 → (NH4)2HPO4). By adjusting the ammonia-to-phosphoric-acid ratio, MAP and DAP are produced as granules, prills, or fine powders used directly as fertilizer blends.

Uses: The primary use is as a fertilizer, supplying nitrogen and phosphorus to crops. MAP is often chosen for starter fertilizers because it supplies phosphorus with relatively low salt concentration; DAP provides balanced phosphorus and nitrogen and is widely used across soil types. Ammonium phosphates are also found in some fire-retardant formulations and in certain dry chemical extinguishing powders.

Properties and safety: They are highly soluble in water and can be hygroscopic, requiring dry storage. Handling dust can irritate the eyes, skin, and respiratory tract. They should be stored away from moisture and incompatible materials, and spilled material should be swept up to minimize environmental discharge. In the environment, runoff containing ammonium phosphates can contribute to eutrophication in water bodies.