Granulating Spray Dried Powders

Wednesday, February 11th, 2015

Problem: While mixing ingredients in solution and spray drying into a fine powder creates a very uniform blend, the fine cohesive nature of many spray dried powders often creates problems in dustiness, flow-ability, and dissolution in downstream processes.

One example of a customer product requirement was:

  • Product dustless, free flowing, specified dissolution rate
  • Ability to run multiple feed stocks
  • Provide complete granulation system
  • Targeted use: specialty fertilizers

Operations considerations included:

  • Corrosive Nature of Material
  • Ability to operate consistently with Hygroscopic material
  • Ability to change granular product size depending on feed stock

Solution: Multiple feed materials were tested in Bepex’s Process Development center. One complete compaction and granulation system, with easy to change parts to best accommodate different feed stocks was developed. Compacting, milling, and screening the fine powder into a granular form solved all four of the customer’s problems. A near dustless and free-flowing granular product readily dissolved into solution without clumping like the fine powder. Additionally, the granulation system was able to run continuously without shutting down due to plugging issues – an issue their previous wet-agglomeration process experienced.

Benefits and Results:

  • Low utility: no addition of moisture and so no drying step
  • No constant shutdowns due to plugging of hygroscopic materials.
  • Complete system supplied
  • Customer able to provide their clients with product significantly easier to mix into solution