About mixing powders and solids
The mixing of powders or granules is required for various industrial processes and must be adapted according to the properties of the raw materials used and final product specifications.
“Tumbler mixers” are based on a relatively simple concept: a closed drum rotates around its axis forcing the particles to tumble over one another on the surface of the mix.
Rotary drum mixers contain no inner moving parts, so maintenance is straight-forward and the gentle mixing action ensures that the properties of fragile or heat-sensitive materials are not affected.
Rotary Drum Mixers are ideal for the homogenization of different powders (premix for building materials), impregnation (flavouring or colouring of food products, catalyst regeneration process with acid in specialty chemicals)…
These rotating drum mixers can also be used to perform powder or fibre granulation operations (for example granulation of fiberglass for use in polymers).
On the other hand, circulation patterns in “convective mixers” are produced by an agitation system set up inside a static shell. This system moves particles in groups from one area to another within the vessel.
Agitation is created with ribbon or blade systems.
Blade mixers generate more intense mechanical action than ribbon mixers. The former adds lots of air to the mix and this tends to fluidize the bed of particles in the vessel and enhance the movement of these particles. As a result, mixing times are shorter than with ribbon mixers.
Intensive blade mixers are some mixer for powders used for numerous industrial mixer applications including the mixing of mineral powder and chemical additives to make exterior wall coatings or tile adhesives, soil or mineral treatment or even the mixing of explosive powders.
Ribbon mixers are used for mixing more fragile products typically found in the food industry or animal feed industry.
Twin-screw mixers with over-lapping paddles have also been developed which are suited to applications that do not require intimate mixing, as is the case with the treatment of contaminated soil for example.
The mixing of divided solids is frequently required in the following fields/industries:
- Plant protection products
- Friction materials
- Facade renders
- Ceramic tile adhesives (cta)
- The food industry
- Environmental management