Laser particle size analysers

Fine-grained dolomite flour was used in the experiments. Raw material for testing was prepared on the basis of five commercially available size fractions of this material classified as <10, <15, <60, <100 and <250 pm. The particle size distribution of each fraction was determined using a laser particle size analyser Analysette 22 and described by the statistical moments. 

Reddish brown (SYR 3/6 to 5/8) sediments are present almost throughout Level C, mostly in the epiphreatic passage (Fig. 5) but also within the enlarged joint that extends upwards beyond the flat roof. The sediments are highly uniform, and consist of abundant angular silt-sized quartz in a reddish clay matrix. Laser particle size analyses of sediment from Bone Chamber (Fig. 6) show that the grain size distribution is polymodal the coarsest grain size (medium-coarse silt) comprises only a small proportion of the... 

Particle size distribution measurements were performed by means of a Leeds Northrop Microtrac Particle Size Analyser, equipped with a laser beam to determine the particle sizes. A water suspension was prepared by addii ca 2g of the sample and a few drops of a suitable detergent. The sample was uhrasonically treated for 1 minute before the analysis was performed. An average of three runs was used to calculate the final particle size distribution. 

Particle size analysis was carried out on a Horiba dynamic laser scattering particle size analyser. Powder X-ray diffraction measurements were performed on a Siemens D500 diffratometer with a monochromated Cu Ka radiation source. SEM analysis was done using a Zeiss Ultra55 Electron Microscope. The gas tightness of non reduced half cells (substrate, anode, and electrolyte, dimensions ... 

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).

Figure 12.11 Schematic of the wide range LA910 laser scattaing particle size analyser. (Courtesy of Htniba Ltd.)...

Another widely used particle size analyser is based on the forward scattering of laser light through a dilute (< 1 % by volume) suspension of crystals retained in a small ( 10mL) agitated cell. The resulting Fraunhofer diffraction pattern is detected and translated, by means of the instrument software, into a particle size distribution (BS ISO 13320, 2000). 

Particle Size. Wet sieve analyses are commonly used in the 20 )J.m (using microsieves) to 150 )J.m size range. Sizes in the 1—10 )J.m range are analyzed by light-transmission Hquid-phase sedimentation, laser beam diffraction, or potentiometric variation methods. Electron microscopy is the only rehable procedure for characterizing submicrometer particles. Scanning electron microscopy is useful for characterizing particle shape, and the relation of particle shape to slurry stabiUty. 

For a given bulk solid, determine particle size distribution, median particle diameter dv50 (e.g., using a Coulter Counter or a Malvern Laser Diffraction Analyser) and ps. 

This is a universally applicable instrument for determining particle-size distributions of all kinds of solids which can be analysed either in suspension in a measuring cell or dry by feeding through a solid particle feeder. In the Fritsch Analysette 22 laser diffraction apparatus the measured particle-size distribution is displayed on the monitor in various forms, either as a frequency distribution, as a summary curve or in tabular form and can be subsequently recorded on a plotter, stored on hard disk or transferred to a central computer via an interface. The time required for one measurement is approximately 2min. 

Light scattering Modem laser light scattering instruments are very advanced devices for particle size distribution analyses. The laser light is scattered by the small dispersed particles or drops. The latter is known to be dependent on the radius of the particle. 

A typical feed composition was 1000 g capsul, 2334 g deionized water and 200 g orange oil. The finished powders were stored in amber bottles at -25prior to accelerated storage study and relevant analyses. Particle Size Analysis. To ascertain the effect of atomizer voltage on the particle size, the particle size distributions of three powders were first determined. The Microtrac laser light particle size analyzer (Medallion Laboratories, Minneapolis, MN) was used in this study. The volume percent data over particle diameter ranging 2.8 p. to 176 jii was recorded. Mean value of the volume percent distribution and calculated surface area were also obtained. 

The samples were subjected to particle size analysis using a laser analyser. Results obtained enabled the calculation... 

The different methods of particle size analysis can be grouped into several categories size range analyses (sieve methods), wet or dry methods, and manual or automatic methods (laser-light). All these methods are described elsewhere. 

The particle size distribution of the as received coal samples was measured by the Microtrac laser diffraction apparatus and size analyses for all samples are given in Table VI. The samples were sieved to remove any particles smaller than 45 pm and larger than 250 pm. The fluid bed feeder was loaded with a 20 to 30 gram coal or mineral sample. The feeder was operated at constant dilution or transport air flow and the coal flow was varied by changing the bed pressure (by either increasing the fluidizing air flow or decreasing the exhaust flow). 

Laser granulometry indicated little variation in the particle size with depth in the trench section, the median size being 12-15 pm. On average the bulk sediments were found to contain approximately 20% clay ( < 2 pm), 70% silt (2-63 pm) and < 10% sand ( > 63 pm). Bulk sediment XRF analyses also showed that the major element proportions are also relatively constant with depth (Figure 7.7). X-ray diffraction (XRD) analyses showed some variability in the relative proportions of clay minerals present in the < 2 pm fraction, but all samples were dominated by illite, smectite, kaolinite and chlorite. The calcium carbonate content was low ( < 1%), much of the detrital material apparently having been dissolved. The sediment pH ranged from 6.2 to 6.7. 

The Particle-Size Distribution (PSD) was determined by the laser light scattering technique [22], using a Malvern M6.10 apparatus. Analyses were performed on water-suspended material after 1 min stirring. 

Figure 12.13 Auto-dilution and optical particle sensor schematic of the Accusizer 770, where MC = mixing chamber, Vi, Vi, V3 = valves, P = pump, OPS = optical particle sensor, LS = laser source, D = detector, V s volts and PHA = pulse height analyser. (Courtesy of Particle Sizing Systems.)...

Coulter LS Series particle size distribution analyser Laser light diffraction 0.1-810 pm 60 Particle sizing... 

A number of expensive but very powerful analysers available on the market are based on Fraunhofer diffraction. An assembly of particles in a liquid or in a gas are illuminated by an expanded laser beam and the particle size distribution is derived from the measurement of the spatial distribution of the diffraction patterns on a flat detector behind the sample. 

Particle size analysis of the gypsum was carried out using a Malvern Mastersize 2000 laser analyser with an accuracy of 1%. As shown in Figure 2, the particles are between 1 pm and 1 mm in diameter, and mostly >300 pm. 

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