Particulate materials

Bag filters. Bag filters, as discussed in Chap. 3 and illustrated in Fig. 3.66, are probably the most common method of separating particulate materials from gases. A cloth or felt filter material is used that is impervious to the particles. Bag filters are suitable for use in very high dust load conditions. They have an extremely high efficiency, but they suflFer from the disadvantage that the pressure drop across them may be high. ... 

Gy, P. M. Sampling of Particulate Materials Theory and Practice Elsevier Amsterdam, 1979. 

An important question to consider when using a flame as an atomization source, is how to correct for the absorption of radiation by the flame. The products of combustion consist of molecular species that may exhibit broad-band absorption, as well as particulate material that may scatter radiation from the source. If this spectral interference is not corrected, then the intensity of the transmitted radiation decreases. The result is an apparent increase in the sam-... 

Plastics. In the plastics industry, the term filler refers to particulate materials that are added to plastic resins in relatively large, ie, over 5%, volume loadings. Except in certain specialty or engineering plastics appHcations, plastics compounders tend to formulate with the objective of optimizing properties at minimum cost rather than maximizing properties at optimum cost. Table 2 fists typical plastic fillers and their uses. 

Because the corrosion resistance of lead and lead alloys is associated with the formation of the protective corrosion film, removal of the film in any way causes rapid attack. Thus the velocity of a solution passing over a surface can lead to significantly increased attack, particularly if the solution contains suspended particulate material. Lead is also attacked rapidly in the presence of high velocity deionised water. The lack of dissolved minerals in such water prevents the formation of an insoluble protective film. In most solutions, lead and lead alloys are resistant to galvanic corrosion because of the formation of a nonconductive corrosion film. In contact with more noble metals, however, lead can undergo galvanic attack which is accelerated by stray electrical currents. 

Particulate Materials. There are three principal classes of particulate magnetic materials y-ferric oxide, y-Fe202, and its modifications chromium dioxide [12018-01 -8] and iron [7439-89-6]. A comparison of the remanent magnetization, and coercivity, for several y-Fe202... 

R. M. German and R. G. lacocca, "Powder Metallurgy Processing and AppHcations for IntermetaUics," Mdvances in Powder Metallurgy (N Particulate Materials, Vol. 6, Metal Powder Industries federation, Princeton, N.J., 1993. 

S-Goncept and Its Application. The assumptions and conditions for deriving equations 7, 11, and 15 impose limitations on the appHcation of the Z-concept and fall into two groups. The first concerns the particulate material. Particles (or drops) are assumed to be spherical in shape and uniform... 

The complete characterization of a particulate material requires development of a functional relationship between crystal size and population or mass. The functional relationship may assume an analytical form (7), but more frequentiy it is necessary to work with data that do not fit such expressions. As such detail may be cumbersome or unavailable for a crystalline product, the material may be more simply (and less completely) described in terms of a single crystal size and a spread of the distribution about that specified dimension. 

Steam-tube dryers are suitable for any particulate material that can be conditioned so as not to stick to metal when dry. Because of relatively iaexpensive heating surface and large capacities, these dryers are probably the most commonly used of the iadirect-heat dryers. Gas- and vapor-tight seals sometimes are built for operations involving dangerous vapors and iaert gas circulation, but these seals are expensive and high maintenance. Small iastaHations excepted, stationary vessels are preferable. 

R. B. Keey, Dying ofEoose and Particulate Materials, Hemisphere Publishing Corp., New York, 1991. 

The success of compression agglomeration depends on the effective utilization and transmission ofthe applied external force and on the ability of the material to form and maintain interparticle bonds during pressure compaction (or consolidation) and decompression. Both these aspects are controlled in turn by the geometiy of the confined space, the nature of the apphed loads and the physical properties of the particulate material and of the confining walls. (See the section on Powder Mechanics and Powder Compaction.)... 

On the other hand, flotation usually imphes the removal of solid particulate material. Most important under the latter category is ore flotation, which is covered separately in Sec. 19. 

Gaseous and particulate pollutants are withdrawn isoldnetically from an emission source and collected in a multicomponent sampling train. Principal components of the train include a high-efficiency glass- or quartz-fiber filter and a packed bed of porous polymeric adsorbent resin (typically XAD-2 or polyurethane foam for PCBs). The filter is used to collect organic-laden particulate materials and the porous polymeric resin to adsorb semivolatile organic species (com-... 

TBT exists in solution as a large univalent cation and forms a neutral complex with CH or OH . It is extremely surface active and so is readily adsorbed onto suspended particulate material. Such adsorption and deposition to the sediments limits its lifetime in the water column. Degradation, via photochemical reactions... 

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