Equipment for Size Reduction

Some of the many kinds of size reduction equipment are described in this section. The best source for complete equipment descriptions is manufacturers catalogs. They often provide technical or expected performance data. Compilations of typical performance information may also be found in the Chemical Engineers Handbook, especially the earlier editions. Chemical Engineers Buyers Guide 2004 (2003) is a source of the companies that manufacture size reduction equipment. 

TABLE 12.5. Operating Ranges for Commonly Used Size Reduction Equipment 

Equipment Size of Feed (mm) Size of Product (mm) Reduction Ratio Capacity (tons/hr) Power Consumption (kW) 

Grinding roller Grinding rmg Revolving bow Tangential air inlet 

A key consideration in the selection of size reduction equipment is the trade-off between the capital cost of the equipment and the operating expenses. This equipment is large, hence a high capital investment, and large quantities of utihties are required, resulting in high operating expenses. 

A hydrocyclone assembly is required to handle 10,000 gpm of slurries of a solid with specific gravity 2.9 with a cutoff point of dx = 100 fim. The allowable pressure is AP = 5 psi. Several slurry concentrations V will be examined. Substituting into Eq. (12.1), with z the function of V in parentheses, 

Some of the many available kinds of size reduction equipment can be described here. Manufacturers catalogs have the most complete descriptions of the equipment and almost always provide typical or expected performance data. Useful compilations of such information are by Taggart (1945) and the Chemical Engineers Handbook (1984, Section 8, as well as older editions). 

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Equipment for size reduction can be categorized by the method in which the necessary stress is appHed to the particles. Figure 3 illustrates the different methods. 

Figure 12.5. Jaw, roll, impact, and tumbling equipment for size reduction, (a) Blake-type jaw crusher operates at 200-300 strokes/min (Allis-Chalmers Co.), (b) Smooth roll crusher, for which operating data are in Table 12.8(b). (c) Swing hammer mill operating data in Table 12.7(a). (d) View of a conical ball mill, showing distributions of balls and material and crusting ranges data in Table 12.6(b) (Hardinge Co.). (e) Tube mill with three compartments, length to diameter ratio 3-5. (f) Rod mill in a cylindrical tumbler, LID = 1.2-1.6 data in Table 12.6(d).

Selection of Size-reduction Equipment. The following factors are determinants in the selection of equipment for size reduction of materials ... 

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