CONTINUOUS PROCESS FOR MANUFACTURING FREELY FLOWING SOLID ACIDIC P/K FERTILIZER

摘要

The invention provides a continuous process for manufacturing a phosphorus/potassium fertilizer from basic chemical commodities. The fertilizer is a free-flowing solid, stable on storage, consisting mainly of a phosphate of formula KH5(P04)2.

主权项

1. A continuous process for manufacturing a solid, free-flowing acidic phosphorus/potassium (P/K) fertilizer, comprising steps of
i) providing agriculturally acceptable phosphoric acid (PA) and partially neutralizing it with a neutralizer selected from monopotassium phosphate (MKP) and potassium hydroxide (KOH), thereby providing an aqueous mixture which provides a pH of less than 3.0 when diluted ten times in water; ii) drying said aqueous mixture of step i) in a vacuum dryer ensuring a reaction temperature between 70 and 120° C. and a pressure of at most 500 mbar whereby obtaining a solid material comprising less than 5 wt % water; iii) cooling down said solid material of step ii) to ambient temperature; and iv) mixing said cooled solid material with a solid magnesium source in an amount of from 0.1 to 3 wt %, based on said cooled solid material;thereby obtaining the free flowing solid fertilizer without tendency to cake, comprising an acidic phosphate of formula KH5(PO4)2 and water in an amount of 5 wt % or less.