Agglomeration processes classification

FIG. 20-71 Classification of agglomeration processes by agitation intensity and compaction pressure. Relative density is with respect to primary particle density and equals (1 — e) where e is the solid volume fraction. Reprinted from Granulation and Coating Technologies for High-Value-Added Industties, Ennis and Litster (1996) with permission of E G Associates. All rights reserved. 

Figure 30 Classification of agglomeration processes by agitation intensity and compaction pressure. (From Refs. 1,2,5.)...

Classification of size enlargement methods reveals two distinct categories (8,39). The first is forming-type processes in which the shape, dimensions, composition, and density of the individual larger pieces formed from finely divided materials are of importance. The second is those processes in which creation of a coarse granular material from fines is the objective, and the characteristics of the individual agglomerates are important only in their effect on the properties of the bulk granular product. 

Another application of tumblers is to the manufacture of mixed fertilizers, in which solid ammonium nitrate, liquid ammonia, liquid phosphoric acid, and liquid sulfuric acid are charged separately and reacted. The incidental agglomeration is excessive, however, and the process must be followed by appropriate crushing and size classification. 

Of course, in any classification system areas of overlap are unavoidable. Some size enlargement processes involve more than one agglomeration mechanism. For example, thermal after-treatment is quite common to harden... 

It is apparent from the data that particles of a few nanometers in size can only be made on industrial scale by synthetic methods. On the other hand, these particles are either intentionally or unintentionally aggregated and agglomerated in their powder forms. Thus, for the dispersion of fillers, agglomerate and aggregate size is usually as relevant as the primaiy particle size. Fillers, which are obtained by various milling and classification processes, can also be obtained in the form of small particles, but usually not below 100 nm. 

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