Semi-batch reactive crystallisation of mono-ammonium phosphate: An experimental study

Johan Utomo, Yusuke Asakuma, Nicoleta Maynard, Kouji Maeda, Keisuke Fukui, Moses O. Tadé

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7 Citations (Scopus)


NH4H2PO4, mono-ammonium phosphate (MAP) and (NH4)2HPO4, di-ammonium phosphate (DAP) have become leading phosphate fertiliser products worldwide. Ammonium phosphates are produced by reactions of ammonia and phosphoric acid resulting in the formation of the mono-basic, di-basic, or tri-basic salts. Inefficiencies in the MAP/DAP production process are due to the lack of a fundamental understanding of the crystallisation-reaction mechanisms. A semi-batch reactive crystalliser equipped with a cooling jacket, a dual feed system and a turbine type agitator has been used in this study. Effects of N/P ratio, seed crystals, feeding system, feed flow rate, initial supersaturation, feeding time and mixing intensity to the real-time supersaturation, crystal yield, crystal shape (aspect ratio) and final crystal size distribution (CSD) were studied in order to understand the kinetics. This study aims to provide new insights into the MAP/DAP reaction-crystallisation mechanisms.

Original languageEnglish
Pages (from-to)594-600
Number of pages7
JournalChemical Engineering Journal
Issue number3
Publication statusPublished - 1 Feb 2010
Externally publishedYes


  • Ammonium phosphate
  • Crystal size distribution
  • Reactive crystallisation
  • Semi-batch crystalliser

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