Validation of surface coating with nanoparticles to improve the flowability of fine cohesive powders--颗粒学报PARTICUOLOGY

Zhu, X., Zhang, Q., Huang, C., Wang, Y., Yang, C., & Wei, F. (2017). Validation of surface coating with nanoparticles to improve the flowability of fine cohesive powders. Particuology, 30, 53-61. https://doi.org/10.1016/j.partic.2016.09.001

Validation of surface coating with nanoparticles to improve the flowability of fine cohesive powders

Xiaolin Zhu ^{a b}, Qiang Zhang ^a *, Cang Huang ^a, Yao Wang ^a, Chaohe Yang ^b, Fei Wei ^a

a Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
b State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, China

10.1016/j.partic.2016.09.001

Volume 30, February 2017, Pages 53-61

Received 3 March 2016, Revised 5 June 2016, Accepted 28 September 2016, Available online 26 November 2016, Version of Record 27 January 2017.

E-mail: zhang-qiang@mails.tsinghua.edu.cn

Highlights

• Mechanism of nano-additives in reducing powder cohesiveness was theoretically analyzed.

• Properly coating with nanoparticles could improve flowability of irregular shape cohesive powders.

• An empirical criterion was proposed to predict coated powder flowability in terms of Co number.

Abstract

Fluidization of fine cohesive powders is seriously restricted by the strong interparticle cohesion. The rational combination of nanoparticles with fine cohesive powders is expected to obtain composite particles with improved flowability. In this work, we firstly reviewed the sandwich and three-point contact models regarding the fundamental principles of nano-additives in reducing cohesiveness. Based on these previous models, the effects of the size of nanoparticles, their agglomeration and coverage on the surface of cohesive powders in reducing interparticle forces were theoretically analyzed. To validate the theory effectiveness for the irregularly shaped cohesive powders, an extreme case of cubic powders coated with silica nanoparticles was fabricated, and the flowability of the composite particles was determined experimentally. Ultimately, based on force balance of a single particle, a semi-theoretical criterion for predicting the fluidization behavior of coated powders was developed to guide the practical applications of improving the flowability of cohesive powders through structural design and modulation.

Graphical abstract

Keywords

Fine cohesive powders; Fluidization; Nanoparticle coating; Interparticle adhesion force; Flowability prediction

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