Dap and Phosphoric Acid Plant Improvements

Author(s) J. Wing
Arab Fertilizer Association (AFA) 24th International Fertilizer Conference and Exhibition, Amman Jordan. Presented November 23, 2011


A selection of attractive modifications are described, based on successful projects.
DAP innovations include:
  • Dual Mole Reactor-Granulator Acid Scrubbing
  • BFL Vaporizer/Scrubber - Vaporizes all ammonia with free heat from air leaving the reactor-granulator acid scrubber. This unit provides a 3rd stage of scrubbing – potentially eliminating need for any tail-gas scrubber.
  • Product Screen Diverter Systems – easy capacity increase
  • Automated Recycle Control - continuously monitors recycle particle size and adjusts process to keep size in mid-range.
  • Dual diameter reactor (pre-neutralizer)
  • Pipe Reactor
  • Cooler Air Chiller
  • Tran-Tech Product Cooler
Phosphoric Acid plant projects to consider include:
  • Conversion from Dihydrate to Hemi: Makes acid at 42% concentration vs. ~27%
    • No need for most evaporation. Usually no rock grinding is needed.
  • Conversion to Hemi-Di – similar benefits plus 98.5% recovery & clean gypsum
  • Utilize gypsum – many ways to make gypsum an asset rather than liability
  • Recover uranium – major investment with high profit potential
  • Recover fluosilicic acid – high-purity grade for AlF3 feed
  • A variety of profitable uses for phosphogypsum
  • Advances in dry gypsum stacking
  • Purify phosphoric acid to technical or food grade
Project management and start-up issues are discussed.