Dispersion stage

Modelling of the dispersion stage in partially filled batch internal... 

On leaving the dispersed air flotation cell, the de-inked stock is further diluted before passing through another fine screening process to remove small solids. The materials are then pumped to a drum thickener prior to he dispersion stage. 

Dispersion is carried out at the lowest acceptable temperature to minimize energy requirements, and is designed to complement the preliminary dispersion action in the pulper. Thickened stock is progressively dewatered to around 40% concentration in preparation for the kneader disperser stage, which breaks down the ink/fiber bonding of more difficult printed materials (123). 

FIG. 21-22 (a) At-line particle sizing MYTOS module courtesy of Sympatec GmbH) based on laser diffraction, with integrated dosing and dry dispersion stage, (b) Module integrated into a Polysius Polab AMT for lab automation in the cement industry. 

Figure 8.6. Suggested arrangement of individual clay platelets at stage 1 (dispersed), stage 2 (aggregated), and stage 3 (both aggregated and flocculated). Platelets are represented schematically, with their thickness exaggerated relative to their diameter.

One may also consider a reverse transition from macroscopic heterogeneous system (surfactant crystals in water) to micellar solutions existing above the Krafft point, via gel formation and its spontaneous dispersion stages. In this case, the swelling of soap upon the penetration of water between the lamella formed with polar ( strongly hydrated) groups occurs prior to the formation of colloidal solution. At sufficient dilutions separation of individual particles, e.g. lamella, from crystals occurs due to the... 

Nearly linear relationship are observed between the gum mixing energy and the viscosity and between the energy for the complete mixing cycle and the viscosity. This indicates that the gum viscosity is controlling not only the mastication step but also the carbon black incorporation and dispersion stages. This experimental observation is well in line with the theoretical considerations above, and current mixing practice. 

Additol VXW 4973 Contraspum 1010 WEN Contraspum 1010 WN TEGO Foamex 800 TEGO Foamex 805 defoamer, dispersion stages Sutfynol DF-60 defoamer, dispersions Agitan 305 Nopco 8034 defoamer, dry biend coatings Antibubble DF-360 defoamer, dry mixes Foamaster PD-1 Powd. defoamer, EB radiation-cured systems EFKA -2721... 

Microemulsion A microemulsion process is the process that two immiscible liquids will go through a dispersion stage where both liquids are stabilized by the surfactant molecules. For example, oil and water are two immiscible liquids. The disperse phase of oil will be surrounded by surfactant molecules. With the desired reactants in the solution, the microdroplets will form and then break to precipitate in the micelles. Acetone and ethanol can be used as solvent for microemulsions to extract the precipitate by changing the structure. Figure 1.4 shows the nanorod synthesis process (Lu et al., 2007). 

The exact composition of Stage I is found by experiment, to give the minimum grinding time and the most stable and complete dispersion. Stages II and III also require care, as hasty additions in an incorrect order can cause the pigment to re-aggregate (flocculate). 

Particles and droplets may become electrostatically charged, particularly during the dispersion stage, by interaction with each other or with nearby surfaces. It has been speculated that charged particle could induce opposite charges on the walls of some airways, resulting in the particles being attracted to the walls and deposited. 

Figure 5.8 Scheme of the dispersion stage of layered silicates in polymers. 

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