Particle-size-grouping method of inclusion agglomeration and its application to water model experiments

T. Nakaoka, S. Taniguchi, K. Matsumoto, S. T. Johansen

Research output: Contribution to journalArticlepeer-review

97 Citations (Scopus)


Agglomeration of inclusions in liquid steel causes not only the enhancement of inclusion removal by flotation but also the increase in the number of large inclusions in final products. To clarify agglomeration behaviour theoretically, a lot of studies have been made until now. However, the behaviour is not clearly understood yet. In this study, a new particle-size-grouping (PSG) method has been established, which enables a simple calculation of the agglomeration by a small number of size groups with complete conservation in total particle volume. This method has been verified by the comparison with the exact solution of a revised population-balance equation. An experimental study of the agglomeration of polyvinyl-toluene latex (PVTL) in a stirred electrolyte solution has been made in an agitated vessel under a rapid agglomeration condition. An effective Hamaker constant of PVTL in water, A131, has been obtained by adjusting the measured agglomeration curve with the curve calculated by the PSG method. Good agreement has been obtained between observed and calculated agglomeration curves for A131=0.8×10-20 J under a wide range of initial particle concentrations and agitation speeds. Numerical simulations of the fluid flow and particle transport in the vessel have been made to confirm the applicability of the PSG method. Computed agglomeration curves agree well with the theoretical curve if the energy dissipation rate averaged with the residence time of liquid in computational cells is used to calculate the dimensionless agglomeration time.

Original languageEnglish
Pages (from-to)1103-1111
Number of pages9
JournalIsij International
Issue number10
Publication statusPublished - 2001
Externally publishedYes


  • Agglomeration coefficient
  • Clean steel
  • Hamaker constant
  • Inclusion
  • K-ε model
  • Model experiment
  • Numerical simulation
  • Turbulent agglomeration

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry


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