Solids mixing and segregation

Complex as this joint process of mixing and segregation is, the mechanism is best understood by studying the simplest case of a binary mixture of two kinds of solid particles having dissimilar properties, e.g., density and/or particle size. 

The general problem of solids mixing and segregation can thus be resolved into three aspects  

How would the two segregated phases of the particle-fluid mixture be juxtaposed with respect to each other—which on top and which below  

How would the mixing process across the phases take place, in the absence of bubbles, the dispersive force balanced against that of segregation  

How would the macro effect of bubbling augment or alter the mixing process  

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Nienow, A. W., and Chiba, T., Solids Mixing and Segregation in Gas-Fluidized Beds, POWTECH 81, Mixing, paper S2/F (1981). 

Chiba S, Kawabata J, Yumiyama M, Tazaki Y, Honma S, Kitano K, Kobayashi H, Chiba T. Pressure effects on solid mixing and segregation in gas-fluidized beds of binary solid mixtures. In Fluidization—Science and Technology (Kwauk M, Kunii, D. eds.). New York Gordon and Breach, 1982, pp 69-78. 

Hirschberg B. Solids mixing and segregation in a circulating fluidized bed. PhD dissertation. Technical University Hamburg-Harburg, 1997. 

Mixing and Segregation of Solid Particles (J.C. Williams and N. Hamby)... 

Williams J. Khan M. The mixing and segregation of particulate solids of different particle size. Chem Eng 1973 7(1) 19-25. 

Bokkers GA, van Sint Annaland M, Kuipers JAM Mixing and segregation in a bidisperse gas-solid fluidised bed a numerical and experimental study. Powder Technol 140 176, 2004. 

Burgess JM, Fane AG, Fell CJD. Measurement and prediction of the mixing and segregation of solids in gas fluidized beds. Pac Chem Eng Congr 2 1405-1412, 1977. 

In summary, the addition of baffles, tubes, and other obstacles restricts large-scale solids movement, reduces the gas and solids backmixing, improves the radial gas and solids mixing, and causes segregation of particles of different sizes. 

Di Felice R, Gibilaro LG, Waldram SP, Foscolo SP. Mixing and segregation in binary-solid liquid fluidised bed. Chem Eng Sci 42 639-652, 1987. 

Matsumoto T, Hidaka N, Takebayasi Y, Morooka S. Axial mixing and segregation in a gas-liquid-solid three-phase fluidized bed of solid particles of different sizes and densities. Chem Eng Sci 52 3961-3970, 1997. 

J. C. Williams and M. I. Kahn, The Mixing and Segregation of Particulate Solids of Different Particle Size, Chemical Engineering, 19, London, p. 169, 1973... 

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