This article explains how combining laser diffraction size analysis with particle shape analysis by optical microscopy can provide more complete information about particle characteristics and lead to more accurate sizing results.
The fast size results provided by laser diffraction (also called laser light scattering) and the method’s versatility in analyzing a wide range of materials have made it the benchmark particle sizing technology for dry bulk materials. In a laser diffraction analyzer, particles in a wet or dry sample are passed before a laser light beam, and the light diffracted by the particles is sensed by receiver optics and converted to a size measurement by computer software. The analyzer is able to work quickly because it bases size measurements on the diffraction of laser light by particles that are assumed to be spherical. When the particle shape isn’t spherical, the analyzer determines the particle diameter from the particle’s measured volume by considering the diameter of a sphere of an equivalent volume.