Glossary

Sedimentation

In mixing and milling technology, sedimentation refers to the process where solid particles settle down in a liquid due to gravity. This often occurs in suspensions where finely ground solid particles are dispersed in a liquid. Sedimentation is a crucial aspect as it can affect the stability and homogeneity of mixtures.

Practically, sedimentation is often undesirable, especially in products that require a uniform distribution of solids in the liquid, such as paints, inks, pharmaceutical suspensions, or food products. When particles sediment:

• They can accumulate at the bottom of the container, leading to uneven concentration in the product.
• The quality of the final product may be compromised as the sedimented particles are often difficult to redisperse.
• To prevent or minimize sedimentation, various strategies can be employed:
• Using thickeners or stabilizers: These additives can increase the viscosity of the liquid, slowing down the sinking of particles.
• Optimizing particle size: Finer milled particles tend to sediment less as their smaller size and higher surface energy keep them in suspension.
• Applying dispersing agents: These help to distribute the particles evenly in the liquid and reduce the attractive forces between particles that can otherwise lead to clumping and sedimentation.

In mixing and milling applications, it is therefore crucial to select both the degree of milling and the composition of the mixture in a way that minimizes sedimentation and achieves a stable, homogeneous suspension.