Granules from fine powder: Agglomaration

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Discussion Overview

The discussion revolves around the challenge of converting fine powder into hard granules using a Fluidized Bed Dryer. Participants explore the effectiveness of using starch as a binder and the parameters that influence the agglomeration process.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant describes their protocol of mixing ~20% starch as a binder and using 50°C air for fluidization, but notes that the resulting granules remain crumbly and soft.
  • Another participant suggests that the issue may lie with the choice of binder, proposing that a binder should wet the metal while maintaining high surface tension and viscosity to ensure granule integrity.
  • A later reply introduces the idea of using a fatty acid salt of the metal as a potential solution for improving the agglomeration process.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the effectiveness of the current method or the best approach to achieve the desired granule hardness. Multiple competing views regarding the binder and its properties remain.

Contextual Notes

Limitations include the lack of detailed information on the specific metal being agglomerated, the exact nature of the fine powder, and the absence of experimental results to validate the proposed solutions.

rollingstein
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I'm trying to convert a fine powder into hard granules (1mm - 3mm dia) & was trying to use a Fluidized Bed Dryer to do it. It seems to somewhat work but the granules stay crumbly & soft rather than the hard product I need.

My protocol is to mix ~20% starch as a binder & then add water & fluidize the bed with 50 C air for about 30 minutes in the hope that the particles agglomerate.

Any tips? What other parameters are relevant?
 
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I'm sorry you are not generating any responses at the moment. Is there any additional information you can share with us? Any new findings?
 
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Greg Bernhardt said:
I'm sorry you are not generating any responses at the moment. Is there any additional information you can share with us? Any new findings?

No, I gave up on the problem. I couldn't find a way to get it to work.
 
The problem may be with the binder. Thinking about it from first principles, you need a binder that will wet the metal, but has a high enough surface tension (and high viscosity would help) to hold the granule together.

If I had to solve this problem, I would be looking at a fatty acid salt of the metal you are trying to agglomerate.
 

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