Aggregative bubbles

Program for design of fluidized bed two phase catalytic reactor % Aggregate bubbling fluidization (gas solid fluidization)... 

The processes that occur in a typical flotation cell are schematically shown in Figure 5 and consist of agitation, particle—bubble coUision and attachment, flotation of particle—bubble aggregates, collection of aggregates in a froth layer at the top of the cell, removal of mineral-laden froth as concentrate, and flow of the nonfloating fraction as tailings slurry. 

Foams Two excellent reviews (Shedlovsky, op. cit. Lemlich, op. cit.) covering the literature pertinent to foams have been published. A foam is formed when bubbles rise to the surface of a liquid and persist for a while without coalescence with one another or without rupture into the vapor space. The formation of foam, then, consists simply of the formation, rise, and aggregation of bubbles in a hquid in which foam can exist. The hfe of foams varies over many magnitudes—from seconds to years—but in general is finite. Maintenance of a foam, therefore, is a dynamic phenomenon. 

In the stirred tank, the final mean size of particles was reduced by the increase of stirring rate, being consistent with increased fluid shear induced particle disruption relative to aggregation. Use of three different gas velocities in the bubble column, however, results in no significant difference in agglomerate size but since the size is relatively small, it may simply reflect an asymptotic value. 

Impinger Midget impinger By bubbling Microscopy Aggregates broken up only particles >1 pm... 

In a DAF thickening process, air is added at pressures in excess of atmospheric pressure (2.1 to 4.9 kg/cm1 2 3 4 30 to 70psig) either to the incoming sludge stream or to a separate liquid stream. When the pressure is reduced and turbulence is created, air in excess of that required for saturation at atmospheric pressure leaves the solution as very small bubbles of 50 to 100 pm in diameter. The bubbles adhere to the suspended particles or become enmeshed in the solids matrix. As the average density of the solids-air aggregate is less than that of water, the agglomerate floats to the surface. The floated solids build to a depth of several inches at the water surface. Skimmers continuously remove the float.58... 

Enhanced particle aggregation by tiny bubble bridging, giving rise to increased collision probability of the enlarged particle aggregates with flotation-sized bubbles... 

The monothiocarbamato complex [Et4Zn(OSGNEt2)2(NEt2)2] was obtained by bubbling GOS through an in situ prepared Zn(NEt2)2 solution.205 Here, the tetranuclear aggregate was low in thiocarbamate and rich in bis(diethy-lamido)zinc, due to the incomplete insertion of GOS. 

Foam - A fluid aggregate of air filled bubbles, formed by chemical means that will float on the surface of flammable liquids or flow over solid surfaces. The foam functions to blanket and extinguish fires and/or prevent the ignition of the material. 

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