A concise treatise on model-based enhancements of cohesive powder properties via dry particle coating

This paper presents a review of our key advances in model-guided dry coating-based enhancements of poor flow and packing of fine cohesive powders. The existing van der Waals force-based particle-contact models are reviewed to elucidate the main mechanism of flow enhancement through silica dry coating. Our multi-asperity model explains the effect of the amount of silica, insufficient flowability enhancements through conventional blending, and the predominant effect of particle surface roughness on cohesion reduction.

Highlights

• Advances in model-guided dry coating of cohesive powder flow enhancement presented.
• Chen-NJCEP model explains the mechanism of dry coating induced flow enhancements.
• Models offered for the guest amount and type, and granular Bond number estimation.
• Dry coating led to drastically enhance flow, packing, agglomeration, dissolution.
• Agglomeration, indicator of flowability, dramatically reduced with dry coating.

Models are presented for the determination of the amount and type of guest particles, and estimation of the granular Bond number, used for cohesion nondimensionalization, based on particle size, particle density, asperity size, surface area coverage, and dispersive surface energy. Selection of the processing conditions for LabRAM, a benchmarking device, is presented followed by key examples of enhancements of flow, packing, agglomeration, and dissolution through the dry coating. Powder agglomeration is shown as a screening indicator of powder flowability. The mixing synergy is identified as a cause for enhanced blend flowability with a minor dry coated constituent at silica < 0.01%. The analysis and outcomes presented in this paper are intended to demonstrate the importance of dry coating as an essential tool for industry practitioners.

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Rajesh Davé, Sangah Kim, Kuriakose Kunnath, Siddharth Tripathi, A concise treatise on model-based enhancements of cohesive powder properties via dry particle coating, Advanced Powder Technology, Volume 33, Issue 11, 2022, 103836, ISSN 0921-8831,
https://doi.org/10.1016/j.apt.2022.103836.