Product properties agglomerates

Fig. 13. Spray-dryer system designed for production of agglomerated food powders with instant properties (82) A, Hquid-feed system B, spray-dryer chamber C, drying air heater D, cyclones for fines recovery E, vibrofluidizer as afterdryer F, vibrofluidizer as aftercooler and G, fines return to drying...

Crystal morphology (i.e., both form and shape) affects crystal appearance solid-liquid separations such as filtration and centrifugation product-handling characteristics such as dust formation, agglomeration, breakage, and washing and product properties such as bulk density, dissolution kinetics, catalytic activity, dispersability, and caking. 

A well-known addition to the basic machine is a separate reroll ring beyond the rim of the main disc (see Fig. 3.14). Formed product-size agglomerates are ejected over the rim into this peripheral ring where they are further smoothed and formed into more spherical shapes. A surface layer of fines, such as coke breeze in iron ore green balls or an anti-caking dust to improve storage properties, may be added in the reroll ring. 

Enhance dosing properties. Agglomerated powders have better flow properties, which makes the dosing of these products easier when used, for example, in vending machines (instant cacao or milk powder)... 

The macroscopic properties of liquid suspensions of fumed powders of silica, alumina etc. are not only affected by the size and structure of primary particles and aggregates, which are determined by the particle synthesis, but as well by the size and structure of agglomerates or mesoscopic clusters, which are determined by the particle-particle interactions, hence by a variety of product- and process-specific factors like the suspending medium, solutes, the solid concentration, or the employed mechanical stress. However, it is still unclear how these secondary and tertiary particle structures can be adequately characterized, and we are a long way from calculating product properties from them [1,2]. 

In summary, the major advantage of this new system is the stability of the latex product properties, and the reduction of the danger of catastrophic agglomeration. Soap levels can readily be set to give stable latex particles and yet generate any required particle concentration. The new system is also more flexible in its ability to be controlled to produce a desired latex product. It should also prove to be less expensive and more flexible than the alternative of seeding the reactors with seed particles generated apriori in batch reactors. 

For those reasons, strength" means many different things in industry. Typically, measurement of strength is based on a simulation of the stresses which a particular agglomerated product must withstand. Very few industrial methods for the determination of this property are standardized or even known. In a competitive environment it is of less interest to compare quality between rivals than to make sure internally that the product properties that are expected by the industrial or public consumer are maintained. Therefore, most measurements of strength are undertaken as quality assurance. A few will be described below as examples. 

Most deviations from the anticipated system efficiencies, design expectations, and product properties of size enlargement by tumble/growth agglomeration are rooted in the mechanisms of bonding and aggregate structure. Reference should be made to Fig. 3.6 (Chapter 3) and Figs. 5.1 and 5.3-5.8 (Chapter 5). 

For high filled products the main criteria for quality is the distribution of the solids in the binder. Only when agglomerates are broken up and the solids are wetted evenly with the binder the desired product properties such as mechanical strength or morphology can be achieved. 

The ratio of fuel and oxidizer is considered one of the most important parameters in determining the properties of synthesized powders obtained by combustion. Product properties such as crystallite size, surface area, morphology, phase, degree and nature of agglomeration, are generally controlled by adjusting the fuel-oxidant ratio. 

Each of the mentioned main constmctive elements of spray fluidized bed equipment can be used to manipulate product properties in the desired direction. For example, droplet size and spray pattern have an influence on the particle wetting and on the local liquid distribution in the fluidized bed - thus also on particle growth kinetics, the type of particle size enlargement (agglomeration in comparison to granulation and coating) and product properties (e.g., particle porosity and density, and surface morphology). 

The changes in power consumption in a typical rubber mix are indicative of stages in the process such as incorporation, dispersion, and plasticization, and can be related to the development of end-product properties (see Fig. 4). At the end of the incorporation stage, the majority of filler is present as rubber-filled pellet fragments. These act as large filler particles, whose effective volume is higher than that of the filler alone, both because of the rubber inside the particles and the rubber immobilized between them. As dispersion proceeds and these agglomerates are broken down, the rubber immobilized between the particles is released into the matrix. 

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