1. Characteristic quantities of divided solids. Powder classification

1.1 Physical quantities

The physical quantities, representative of monodisperse divided solids, are essentially their true density, i.e. ρ _s , and their diameter d _p .

• In the case of non-spherical particles, we define d _p as the diameter of an equivalent sphere, having the same volume as that of the particle under consideration. We then introduce a sphericity factor Φ _s , defined as the ratio between the surface area of a sphere of the same volume as the particle, to its true external surface areaS _p