Patent ID: 9278890
Filing Date: 2016-03-08
CPC Classification: C01B,C05B,C05D,C05G

Claim Text:
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) in an aqueous solution and partially neutralizing it with an aqueous neutralizer selected from the group consisting of monopotassium phosphate (MKP) and potassium hydroxide (KOH) in a reactor kept at a temperature of from 70 to 120° C., wherein said MKP and said KOH are in an amount of from 1.32 to 1.85 and from 0.28 to 0.33, respectively, weight parts per one weight part of PA, to obtain thereby providing an aqueous mixture; 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 to obtain 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 selected from the group consisting of magnesium oxide, magnesium hydroxide, and magnesium carbonate in an amount of from 0.1 to 3 wt %, based on said cooled solid material so as to obtain the free flowing solid fertilizer without tendency to cake, comprising an acidic phosphate of formula KH