Kinetics of agglomeration

Heterodisperse Suspensions. The rate laws given above apply to monodisperse colloids. In polydisperse systems the particle size and the distribution of particle sizes have pronounced effects on the kinetics of agglomeration (O Melia, 1978). For the various transport mechanisms (Brownian diffusion, fluid shear, and differential settling), the rates at which particles come into contact are given in Table 7.2. 

When two similarly charged colloid particles, under the influence of the EDL, come close to each other, they will begin to interact. The potentials will detect one another, and this will lead to various consequences. The charged molecules or particles will be under both van der Waals and electrostatic interaction forces. The van der Waals forces, which operate at a short distance between particles, will give rise to strong attraction forces. The potential of the mean force between colloid particle in an electrolyte solution plays a central role in the phase behavior and the kinetics of agglomeration in colloidal dispersions. This kind of investigation is important in these various industries ... 

Revised and expanded, this second edition features new chapters on the kinetics of agglomeration of noncoale.seing particles and the fundamentals of aerosol reactor design. It covers the effecLs of turbulence on coagulation and gas-to-particle conversion and also di.scusses the formation of primary particles by the coltision-coale.scence niechani.sm. The chapter on the atmo.spheric aerosol has been completely rewritten within the aero.sol dynamics framework. Its basic approach and topicality make Smoke, Dust, and Haze Fundamentals of Aerosol Dynamics, 2le, an essential guide for both studenfs and researchers. 

The attrition index Ai (Equation 32) proposed by Barletta and Barbosa-Canovas (1993a) was found suitable for studying agglomeration and the effects of agglomerate size and water activity on the attrition kinetics of agglomerated coffee and nonfat milk (Yan and Barbosa-Canovas, 2001a). 

For further information on the kinetics of agglomeration in pans a study by W. Dbtsch [B.33] should be referred to also. 

Agglomerierteller (Kinetics of agglomeration for the simulation of agglomeration processes in the pan granulator)... 

Features of particle flocculation and gelation in colloids of considerable significance for ceramics are (1) The kinetics of agglomeration. How fast do particles in suspension agglomerate (2) The structure of agglomerates. How many particle aggregates of a given size are formed ... 

The kinetics of agglomeration can be understood as a quasi-bimolecular reaction. If only particles of one size are concerned, the kinetics can be described by Equation 4.1, with N as density of these particles. Here, a denotes the efficiency of the bimolecular collisions ... 

Hostomsky, J. and Jones, A.G., 1993b. Ibid., Crystallization and agglomeration kinetics of calcium carbonate and barium sulphate in the MSMPR crystallizer. Indem. pp. 2049-2054. 

Illustration Kinetics of dispersion the two-zone model. The models for agglomerate rupture when integrated with a flow model are useful for the modeling of dispersion in practical mixers, as was discussed for the case of drop dispersion. Manas-Zloczower, Nir, and Tadmor (1982), in an early study, presented a model for the dispersion of carbon black in rubber in a Banbury mixer (Fig. 34). The model is based on several simplifying assumptions Fragmentation is assumed to occur by rupture alone, and each rupture produces two equal-sized fragments. Rupture is assumed to occur... 

Kawashima, Y., and Capes, C. E., Further studies of the kinetics of spherical agglomeration in a stirred vessel. Powder Technol. 13, 279 (1976). 

As discussed in Chapter 15, the size distribution of particles in an agglomeration process is essentially determined by a population balance that depends on the kinetics of the various processes taking place simultaneously, some of which result in particle growth and some in particle degradation. In a batch process, an equilibrium condition will eventually be established with the net rates of formation and destruction of particles of each size reaching an equilibrium condition. In a continuous process, there is the additional complication that the residence time distribution of particles of each size has an important influence. 

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