Ammonium polyphosphate

Description

Ammonium polyphosphates are liquid fertilizers with compositions up to 11-37-0, manufactured by the reaction of anhydrous ammonia with superphosphoric acid. Superphosphoric acid is made by the concentration of regular wet-process acid up to P2O5 concentrations of 78%. Granular polyphosphates suitable for bulk blending are made by reacting ammonia with regular wet process acid of 52% P2O5 content and using the heat of reaction to drive off water to produce a phosphate melt of 10-43-0, with about 40% of the phosphorus in the polyphosphate form.

Agricultural Uses

Ammonium polyphosphate fertilizer is a unique liquid nitrogen-phosphorus fertilizer produced in Russia only by PhosAgro. Maximum phosphorus availability and absorption by plants compared to traditional solid phosphorus-based fertilizers, especially on soils with high calcium carbonate content. It ensures yield increase for different crops during foliar application. It is most effective in dry weather conditions. It is easy to store on farms.

Solubility in water

Ammonium polyphosphate (APP) is a branched or linear polymeric compound with a variable degree of polymerization (n). Generally, Ammonium polyphosphate of a low degree of polymerization (n ≤ 100, crystalline form I) is water soluble or water sensitive, while APP with longer chains (n ≥ 1000, crystalline form II) displays a very low water solubility (<0.1 g/100 mL). In general, long-chain APP starts to degrade at above 300°C, generating ammonia and polyphosphoric acid, while the short-chain one begins decomposing at 150°C.