Powders, granulates, suspensions and emulsions

Ruhr Lab GmbH can determine the particle size distribution of various matrices using different methods. In addition to the classic sieve analysis for coarser dusts, for example, we measure particle sizes between 0.9 µm and 875 µm, both dry and wet dispersed, using the laser diffraction method in accordance with ISO 13320. This type of determination using scattered light measurement is used in research through to production control due to fast and reproducible measurements.

Measuring principle / measuring method

In laser diffraction, particle size distributions are determined by measuring the angular dependence of the intensity of scattered light from a laser beam that passes through a dispersed particle sample. Large particles scatter light at small angles relative to the laser beam, while small particles lead to large scattering angles. The data of the angle-dependent scattered light intensity is analysed and forms the basis for calculating the size of the particles responsible for the diffraction pattern. The Fraunhofer theory is used here, without the knowledge of optical constants. The particle size is specified as the equivalent diameter of the diffraction-equivalent sphere.