1. Blending and homogeneity

1.1 Homogeneity, a multi-scale concept

The aim of any operation involving the mixing of divided solids is to produce, either from different streams of solids (continuously), or from different layers of solids (discontinuously), or even from a premix of these constituents, a certain quantity of material whose homogeneity must satisfy a particular use.

For a given application, it is therefore not useful to produce an intimate mixture at the particle scale, but directly at the scale which confers the expected properties of use, known as the observation scale. At first sight, this scale may correspond to the quantity of material present in the volume of the elementary packaging of a mixture (tablet, capsule, sachet, bag...). But if the achievement of a property...