Verfahren und Vorrichtung zur Herstellung von Ammoniumpolyphosphatloesungen oder- konzentraten

摘要

Ammonium polyphosphate solns of use as liquid fertilisers, are prepd by counter-current mixing of two reagent streams at least one of which is preheated in a reactor of length:diam ratio >=50 and at a space velocity of 8.5-9.0 sec -1. The stream comprises wet process phosphoric acid (preheated to 135-143 degrees) and NH3 (preheated to 149-166 degrees), and conditions are chosen such that a reactor temp. of 232 degrees-260 degrees is maintained. The effluent is cooled by mixing with a spray of product at 71 degrees. The process is less costly than prior art.