Optimal particle size

The cmde copper phthalocyanine must be treated to obtain a satisfactory pigment in regard to the crystal modification and optimal particle size... 

Sadler, I.. Y. and Sim, K. G. Minimize Solid-Liquid Mixture Viscosity by Optimizing Particle Size Distribution, Chem. Eng. Prog, V. 87, No. 3, 1991. 

The most challenging part of rubber mixing is the dispersion of the filler The filler agglomerates have to be broken into smaller particles, the aggregates, but not completely to the level of primary particles. An optimal particle size distribution has to be achieved in order to obtain the best properties of the final rubber product [14]. 

A certain amount of shearing forces have to be applied in order to overcome the surface forces that maintain the adhesion between agglomerated pigment crystals. In practice, the shearing forces that are necessary to reduce the particles in a given pigment sample to smaller or even optimal particle size, i.e., the dispersibility of a pigment powder, depends on a number of factors ... 

Controlled optimal particle size and size distribution ensures superior flow properties of coprocessed excipients and reduced reliance on addition of glidants. The volumetric flow properties of SMCC were studied in comparison with those of the physical mixture of its parent excipients (42). The particle size range of the two test samples was found to be similar, but the flow of coprocessed excipient was better than that of the physical mixture. A comparison of the flow properties of Cellactose with its parent excipients was also performed (5) by measuring the angle of repose and Hausner ratio, and Cellactose was found to have better flow characteristics than lactose or a physical mixture of cellulose and lactose. The spray-dried coprocessed product had a spherical shape and even surfaces, which resulted in improved flow properties. On similar terms, mechanically coating the 2% CSD over microfine cellulose powder resulted in improving its flow properties (43). 

The customary compn of AN-gas oil mixts, the optimal particle-size distribution of the AN, protection against atm moisture, and the prepn of expl mixts on location are discussed. 

Table 7. Refractive indices and optimal particle sizes of some white pigments (). = 550 nm) calculated according to the van de Hulst formula [1.27]...

Pigment Formula Mean refractive index Optimal particle size (relative to binder) Popt, pm... 

The top curve in Figure 8 applies to pigments with a high absorption index k and low refractive index rt (e.g., carbon black) and shows that the optimal particle size lies below a given limit. 

Because the oxidation reaction is highly exothermic, the temperature in the combustion chamber reaches 1200°C and microcrystals of zinc oxide are formed. By controlling the reaction conditions in the combustion chamber, zinc oxide having an optimal particle size (400—700 nm) can be produced. In combustion chambers, an excess of air (30—50%) must be maintained to prevent the undesirable reaction of zinc vapors and zinc oxide with combustion by-products. 

Using particles substantially smaller than about 40 to 80 mesh leads to too large a flow resistance, and productivity drops. Thus, an optimal particle size exists, and in general this will lie in the range of 20 to 120 mesh. 

The milling operation will reduce the particle size of the dried granulation. The resultant particle size distribution will affect such material properties as flow, compressibility, disintegration, and dissolution. An optimal particle size/size distribution for the formulation will need to be determined. 

The first two are important for the last one it is only important that the polyester is fine enough to allow a good distribution of the cross-linker throughout the particle. You take its diameter equal to that of the cross-linker sub-particle. To get an idea of the optimal particle size, you will need to analyse the spraying operation. We will not do that here we only note that it requires particles of the order of 30 pm in diameter. The spraying analysis will also tell us that the maximum layer thickness is a few times the diameter of the particles. 

Equations (4.91) and (4.92) allow the optimal particle size of the active component to be determined, which provides the maximal stationary rate of the catalytic transformation for a given mass of the dispersed active component. In the case of the uniformly dispersed active component, rate V-Z of catalytic transformations under kineticaUy controlled conditions equals... 

The same slurry-coating method is applicable to catalyst particles, and the same reasoning holds for an optimal particle size. Different is the impact of fhe use of binder material. 

Opacity, optimum performance is found for medium shades, which can be explained by achieving a compromise between particle size (scattering) and lightness value (absorption) [3.94]. High strength versions have been introduced which both optimize particle size distribution and the amount of coloring ions that are included as dopants in the titanium oxide rutile structure. 

Optimize particle size squared over bed length... 

---