Crystalline particle, diameter size

Coefficient of Variation One of the problems confronting any user or designer of crystallization equipment is the expected particle-size distribution of the solids leaving the system and how this distribution may be adequately described. Most crystalline-product distributions plotted on arithmetic-probability paper will exhibit a straight line for a considerable portion of the plotted distribution. In this type of plot the particle diameter should be plotted as the ordinate and the cumulative percent on the log-probability scale as the abscissa. 

The glass population which entered the fireball earlier and was subjected to more heating is the more abundant and is peaked at larger particle diameter than is the crystalline population. The size range of the over-all population is from a few tenths of a micron to perhaps a... 

Moisture content slightly hygroscopic. A well-defined crystalline hydrate is not formed although surface moisture may be picked up or contained within small pores in the crystal structure. At relative humidities between about 15% and 65%, the equilibrium moisture content at 25°C is about 2.0%. At relative humidities above about 75%, tribasic calcium phosphate may absorb small amounts of moisture. Particle size distribution Tribasic calcium phosphate powder typical particle diameter 5-10 pm 98% of particles <44 pm. 

Catalysts used in this process are of two types. Special acid-washed clays of particle diameters in the 200-400- xm range are used in fluidized bed versions of cracking [19]. In these units the catalyst is kept suspended or fluffed up on an upward moving stream of hot gas oil vapors, which ensures continuous exposure of all catalyst faces to the raw material and provides continuous turnover of catalyst. Synthetic catalysts are prepared from a mixture of 85-90% silica and 10-15% alumina, or from synthetic crystalline zeolites (molecular sieves) [19]. They are either used in a small particle size suitable for use in a fluidized bed, or can be formed into 3- to 4-mm diameter pellets appropriate for crackers, which use a moving bed for catalyst cycling. 

The size classification of aerosol particles is greatly facilitated if the particles are assumed to have a spherical shape. The size is then defined by their radius or diameter. The assumption clearly is an idealization, as crystalline particles come in various geometrical, but definitely nonspherical, shapes and amorphous particles are rarely perfectly spherical. At sufficiently high relative humidities, however, water-soluble particles turn into concentrated-solution droplets, which are essentially spherical, and therein lies the most convincing justification for the assumption of spherical particles. 

Carbon blacks are distinguished from most other carbons by their extremely small particle sizes and by the very broad range of particle sizes that can be produced. Primary particles are defined as the roughly spherical regions of rotational crystalline domains within amorphous carbon. The primary particle diameter (fineness) is used to describe the primary particle dimension. Prior to any graphitization treatment, the microstructure of the primary particle is turbostratic. However, significant differences exist between carbon black types that are related to the sizes... 

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