Size methods centrifuge

Methods for making both forms solvent-soluble were the subject of many patents and closely guarded industrial secrets, but much of the mystery was cleared up in two papers by Gerstner [23] and Smith and Easton [24] published in 1966, by which time X-ray diffraction, electron microscopy and disc centrifuge particle sizing methods had been brought to bear on the problem. 

The disk centrifuge is an excellent instrument for determining particle size distributions in the size range from several micrometers to somewhat below 0.1 ym. For broad or especially multimodal size distributions, disk centrifugation is, overall, probably superior to any other sizing method for the aforementioned range. 

Two methods are mainly used for the determination of particle size of inorganic pigments Sedimentation methods (centrifuges) and Fraunhofer diffraction with additional correction due to Mie scattering. 

The solution of the integral for measuring the concentration at constant position over time is only approximately possible. A common way uses Kamack s equation [Kamack, Br. J. Appll. Phys., 5, 1962-1968 (1972)] as recommend by ISO 13318 Part 1 Determination of Particle Size by Centrifugal Liquid Sedimentation Methods). 

BS ISO 13318 (2000) Particle size analysis - centrifugal sedimentation methods. British Standards Institution, London. 

Sedimentation is another classical particle classification and sizing method for liquid-bom particles. Sedimentation methods are based on the rate of settling of particles in a liquid at rest under a gravitational or centrifugal field. The relationship between settling velocity and particle size is reduced to the Stokes equation at low Reynolds numbers ... 

Beckman Elutriation Method. The Beckman elutriation method uses a chamber designed so that the centrifugal effect of the radial inward fluid flow is constant (Fig. 3). The separation chambers are made of transparent epoxy resin which faciUtates observation of the movements of the cell boundary in strobe light illumination. This enables detection of the radius at which the cells are separating. When a mixture of cells, eg, mononuclear white cells, enters the chamber, separation can be achieved by fine tuning centrifuge speed and inward fluid flow to the specific cell group. This is a laboratory method suitable for relatively small numbers of cells. Chambers are available in sizes to handle 2-3 x 10 , 1 2 x 10 , and 1 x 10 ° cells. The Beckman chambers can be appHed to collect mononuclear cells from bone marrow aspirates. 

The reaction mixture can either be crystallised, centrifuged, and dried, or spray-dried and cyclone-separated to produce a fine crystalline powder having a particle size of 50 p.m. Metal analysis of the AP produced by this method is reported to be less than 0.02 p.g/g. 

For determination of the aerodynamic diameters of particles, the most commonly apphcable methods for particle-size analysis are those based on inertia aerosol centrifuges, cyclones, and inertial impactors (Lundgren et al.. Aerosol Measurement, University of Florida, Gainesville, 1979 and Liu, Fine Paiiicles—Aerosol Generation, Measurement, Sampling, and Analysis, Academic, New York, 1976). Impactors are the most commonly used. Nevertheless, impactor measurements are subject to numerous errors [Rao and Whitby, Am. Ind. Hyg. A.s.soc.]., 38, 174 (1977) Marple and WiUeke, "Inertial Impactors, in Lundgren et al.. Aerosol Measurement and Fuchs, "Aerosol Impactors, in Shaw, Fundamentals of Aerosol Sci-... 

Centrifugal Sedimentation Methods These methods extend sedimentation methods into the submicron size range. Sizes are calculated from a modified version of Stokes equation ... 

We wish to separate titanium dioxide particles from a water suspension. The method chosen is centrifugation. The unit is a continuous solid-bowl type with a bowl diamter of 400 mm, a length to width ratio of 3.0, and the unit operates at 2,000 rpm. The feed contains 18 % (weight basis) solids and is fed to the unit at 2,500 Liters/hr at a temperature of 95° F. The average particle size is 65 /tm. (a) Determine the amount of solids recovered per hour (b) Determine the solids concentration in the centrate (c) Determine the horsepower requirments for the centrifuge (d) Size a graviy settler to remove an additional 15 % of the solids. 

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