Solid mixing involves the following mechanisms:
Convective Mixing:
Bulk movement of particles through mechanical means such as blenders, mixers, or tumblers.
Large masses of material are moved from one location to another, promoting mixing.
Diffusive Mixing:
Random movement of individual particles within the bulk.
This is akin to the concept of diffusion but at a particulate level, leading to a more uniform distribution over time.
Shear Mixing:
Application of shear forces that cause layers of particles to slide over each other.
This is often seen in high-shear mixers and can break agglomerates and improve homogeneity.
Tumbling Mixing:
Using rotating drums or V-blenders where gravity causes the particles to tumble and mix as the container rotates.
Solid Mixing Equipment
Ribbon Blenders: Use helical ribbons to move solids within a stationary trough.
Tumble Mixers: Rotate a container to mix particles through tumbling action.
Fluidized Bed Mixers: Use gas or air to suspend and mix particles in a fluid-like state.