Particle
Size Analysis
An analytical technique by which the distribution of sizes in a sample
of particulate material is measured and reported. The particle may be solid
or liquid. Numerous analytical techniques and approaches exist for particle
size analysis.
Particle size analysis is an important tool in characterizing a wide range of final-product performance factors. Selecting the most appropriate instrument for a given application depends on a number of variables. The user must determine those factors that are most important for their application when considering the multitude of alternative particle sizing techniques and models.
Particle size analyzers range from the historical sieve to modern automated light scattering instruments. The most appropriate selection for a particular application depends on a number of factors including the size range of interest, nature of the sample, the information required from the analysis, the analytical method, and sample throughput.
The technical staff at HORIBA is always ready to discuss your application and help select the analyzer that will provide the most useful data.
Size Range
To choose between different models, the size range is usually the prime
factor. Identify not just the median size, but the full range of sizes
in the distribution when reviewing the analyzer specifications. In
areas where more than one instrument has overlapping capabilities,
consider other product types that might be run on the same analyzer
and possible future developments of the product.
Analytical Technique
Modern static light scattering instruments have become the method of
choice in most industries due to
-
their analysis speed (approximately 30 seconds)
-
wide size range
- ease of use
- flexibility
- reproducibility
Their somewhat higher cost is balanced by their greater productivity that traditional methods and tighter control on production processes. For quality control applications, the entire process can be automated, eliminating operator error and providing consistent feedback. The Partica LA-950 is the highest capability model in HORIBA’s range, with a full range of accessories.
Digital image processing is capable of providing shape information, a critical parameter for materials where the particle length, aspect ratio, sphericity, or other shape parameter is important to final product performance. The Camsizer is the instrument of choice for these applications.
Dynamic light scattering is most appropriate for smaller size ranges, but the LB-550 also has the advantage of being able to run at higher concentrations (up to 40 wt%) than previous PCS-type instruments.
Sample Requirements
Different analytical techniques allow the use of different accessories
or sampling systems that may be more appropriate for the material of
interest. They may also be more sensitive to a particular product parameter
than other techniques. Consultation with the vendor's experts will
help in determining the most appropriate selection.
For example, a fragile agglomerated powder or highly-soluble material would be best analyzed as a dry powder by static light scattering instruments. Materials with limited availability or that are toxic or expensive would require a small volume measurement cell available with several different analyzer systems. Samples that are sensitive to dilution would require analyzers like the LB-550 or DT-1200 that are able to measure at higher concentrations.
