Handling of powders - Particle size and shape analysis

Particle size distribution and the characteristic parameters of this distribution are among the most sought-after parameters of a powder, both for predicting its behavior and for calculating the operations that use it: storage, flow, separation, fluidization, heat exchange, chemical reactions, dispersion, dissolution, etc.

This article deals with the particle size distribution and morphology of divided solids. First, it introduces the basic concepts associated with determining the morphogranulometric properties of individual particles (characteristic sizes, equivalent diameters, form factors, sphericity factors). It then describes the theoretical methods commonly used to present and rigorously exploit data relating to a population of particles (size distribution, mean size, granulometric dispersion, distribution laws, graphical or mathematical representations). Finally, it presents the main experimental techniques used for particle size analysis of powders (sieving, image analysis, optical, gravitational, etc.), describing the physical principles corresponding to each technique. Emphasis is placed on the nature of the data obtained, specifying the characteristic size measured by each technique and the basis of measurement (by number or mass). The aim is to provide the information needed to help the reader make the right choice of method for the industrial application in question.