ORALS

SESSION: IronMonPM1-R1	Afonso International Symposium on Advanced Sustainable Iron and Steel Making(6th Intl. Symp. on Advanced Sustainable Iron and Steel Making)
Mon Nov, 5 2018 / Room: Mar Azul (50/1st)
Session Chairs: Tateo Usui; Jose Carlos D Abreu; Session Monitor: TBA

15:15: [IronMonPM108]
Theoretical and Experimental Studies on Agglomeration of Fine Particles and Dispersion of Agglomerated Particles in Liquid
Yoshiei Kato¹ ; Md. Azhar Uddin¹ ; ¹Okayama University, Okayama, Japan;
Paper Id: 110 [Abstract]

For obtaining clean steel, it is important to remove nonmetallic inclusions from molten steel by agglomeration or dispersion of particles. Cold model experiments were carried out by using polymethymethacrylate (PMMA) particles of 2.8m in mean diameter and 3.0 mol/L KCl solution as solid and liquid phases, respectively, and compared with the calculated results of newly developed mathematical models. Three kinds of mixing practices were examined: mechanical stirring by an impeller, gas blowing, and ultrasonic irradiation. The PMMA agglomeration rate of impeller mixing explained by a turbulence agglomeration model was larger than that of gas blowing at the same energy input rate. By introducing a breakup model where the adhered particles on the bubbles were divided on the free liquid surface, the calculated results agreed well with the experiment. The ultrasonic irradiation promoted the dispersion of agglomerated particles, and the dispersion rate increased with the decreasing ultrasonic irradiation frequency and increasing electric power. However, as for impeller mixing, the dispersion proceeded at higher rotation speed and agglomeration occurred at lower speed. Based on the experimental results, mathematical models for ultrasonic irradiation and impeller mixing were developed, and the calculation of the temporal change in total number of particles agreed well with the experiment.

References:
[1] S. Sumitomo, K. Yoshitomi, M.A. Uddin, Y. Kato: ISIJ Int., 58(2018), 1-9
[2] T. Nakaoka: Kobe Steel Eng. Rep.,56(2006), 40-43
[3] S. Sumitomo, H. Koizumi, M.A. Uddin, Y. Kato: Ultrasonics-Sonochemistry, 40(2018), 822-831