Sedigraph particle analyzer

Example 1.1 One of the applications of using Stokes s law to determine the particle size is the Sedigraph particle analyzer. Table El.l shows the relationship between the cumulative weight percentage of particles and the corresponding particle terminal velocities for a powder sample. The densities of the particle and the dispersing liquid are 2,200 and 745 kg/m3, respectively. The liquid viscosity is 1.156 x 10-3 kg/m s. Find out the relationship of the mass fraction distribution to the equivalent dynamic diameter. 

Method of analysis (Re-Tap sieve shaker, SediGraph particle size analyzer, or other equipment) ... 

When comparing results with other methods it is often necessary to dilute the suspensions without changing their state of agglomeration. Despite this, under electrokinetically stable conditions, excellent agreement was found in a comparison with the Mastersizer S, the Ultra Fine Particle Analyzer, the Sedigraph 5000D and scanning electron microscopy [265]. It was stressed however that sample preparation procedure was important. 

Mica products are usually analyzed by screening to determine particle distributions. Specifications typically include minimum and maximum values for the amount of mica passing or retained on screens of varying mesh sizes. Another value often used for a material specification is loose bulk density. Laser particle size analysis is also being used to some extent to define mica products. One should remember that most other minerals are measured by an instrument called a sedigraph, which measures the size of particles based on their settling rate. This procedure can be used with very small low-aspect ratio minerals such as calcium carbonate, talc, silica, very small particle size mica, and aluminum trihydrate but cannot be used for analysis of most mica products. Sedigraph particle size values for very small mica products are about one-half to one-third of the values obtained by laser diffraction. 

EXAMPLE 2.2 Use of the Sedimentation Equation for Particle Size Determination. A titanium dioxide pigment of density 4.12 g cm 3 is suspended in water at 33°C. At this temperature, the density and viscosity of water are 0.9947 g cm-3 and 7.523 10-3 P, respectively. A particle size analyzer (SediGraph, Micromeritics Instruments Corp., Norcross, GA 30093) plots the following data for cumulative weight percent versus equivalent spherical radius ... 

Particle Size Analysis. Particle size distribution measurements of the dry resin were made using a Micromeritics Sedigraph 5000D particle size analyzer. This instrument employs a gravity settling technique and uses Stokes law to determine the particle size. The PSD was run over the size range of 0.36 to 100 micrometers. All measurements were made in dibutyl sebacate as the suspending medium. 

Figure 3. Pints of mean particle size versus standard deviation of two prepared mixtures of standards analyzed by selected automated electronic particle size analysers (from Syvitski et al 1991a). The expected value is shown with a black box. S SediGraph C. Coulter Counter M Malvern laser panicle. sizer G Galai CIS-1, L Lumosed photosedimentometer lA Image analysis (Syvitski et al.. 1991a).

The dry samples of silica-coated alumina were analyzed by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Specific surface area was determined by nitrogen adsorption (BET). Particle-size determination was made by low-angle forward scattering of light from a laser beam (Leeds and Northrup s Microtrac particle sizer) and by monitoring sedimentation with a finely collimated beam of low-energy x-rays and a detector (Micromeritics Sedigraph 5100). 

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