Study on the Preparation of Agricultural Ammonium Polyphosphate
Using residual acid,synthetic ammonia and urea from the by-products of wet process phosphoric acid solvent as raw materials,agri-cultural ammonium polyphosphate was prepared by pre-neutralization reaction repolymerization,and the influence of MER value,raw material ratio,heating rate and reaction temperature on the synthesis of agricultural ammonium polyphosphate was investigated.The test shows that the higher the MER value is not conducive to the synthesis of agricultural ammonium polyphosphate.The increased reaction temperature and neu-tralization degree are favorable for the product polymerization rate index.The total nutrient of agricultural ammonium polyphosphate decreased with the increase of the heating rate,but the neutralization of the pre-neutralization process had little influence on it.Within a certain range,n(phosphoric acid)∶n(urea)was 1∶1.2,and when the reaction temperature was 197℃,the highest total nutrient was 64％and 62％,re-spectively.
Extraction of Residual AcidAmmonificationAgricultural Ammonium Polyphosphate
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