Ammonium dihydrogen phosphate, also known as monoammonium phosphate (abbreviated as MAP), has the molecular formula NH₄H₂PO₄. It is easily soluble in water, and its aqueous solution is acidic. It mainly uses a single ammonia neutralization process, with the neutralization degree controlled at around 1.00. There are generally two granulation methods: spray granulation drying and spray drying. The most common method is to produce powdery monoammonium phosphate by spray drying, which is mainly used as a raw material for the production of compound fertilizers.
Diammonium hydrogen phosphate, also known as diammonium phosphate (abbreviated as DAP), has the molecular formula (NH₄)₂HPO₄. It is also easily soluble in water but insoluble in ethanol. It mainly adopts a secondary ammonia neutralization on the basis of a single ammonia neutralization, increasing the neutralization degree of the slurry to around 1.70, and the neutralization degree of the finished product reaches around 1.50. The spray granulation process is used for granulation, and we mainly use it to produce granular products.
1. The density of ammonium dihydrogen phosphateis higher than that of diammonium hydrogen phosphate, which is very beneficial for packaging, storage, and transportation.
2. The stability and critical relative humidity of ammonium dihydrogen phosphate are higher than those of diammonium hydrogen phosphate.
3. The ammonia vapor pressure of ammonium dihydrogen phosphate is very low, so the ammonia loss during the production and use processes is smaller than that of diammonium hydrogen phosphate.
4. When diammonium hydrogen phosphate is mixed with superphosphate, it agglomerates due to the formation of calcium dihydrogen phosphate, and the water solubility of phosphorus pentoxide decreases. When ammonium dihydrogen phosphate is mixed with superphosphate, the degree of degradation is relatively small.
5. The mass fraction of phosphorus pentoxide in ammonium dihydrogen phosphate can reach 52%, which is more suitable for areas with phosphorus deficiency and nitrogen abundance.
6. As a phosphorus raw material for compound mixed fertilizers or blended fertilizers, ammonium dihydrogen phosphate has a wider application range than diammonium hydrogen phosphate.
7. Diammonium hydrogen phosphate has a high nitrogen content. For manufacturers, they can take advantage of its nitrogen content to make profits, and it is currently widely used in blended fertilizers. For farmers, it is necessary to choose ammonium dihydrogen phosphate according to the soil properties.
8. Diammonium hydrogen phosphate is a high-concentration quick-acting fertilizer that can be used on various crops and soils, especially suitable for crops that prefer ammonium and require phosphorus.
