Classification

The classification (or dimensional classification) of materials has the goal of:

• Producing particle-size diameters for commercialisation (calcareous aggregates, charcoal grades, plastic pellets, wood pellets, etc.);
• Preparing materials for a differentiated downstream processing of the particle-size classes which constitute it (granulating fines and fragmentation of coarse grains)
• Preparing materials to for a demanding treatment prior to a defillering (dedusting) or conversely a removal of fractions which are too coarse.

In the case of mixed materials, it also enables carrying out a first stage of purification or concentration of one of the components, a principle followed in certain waste recycling processes in particular.

The choice of classification techniques is primarily dictated by the grain size of the material to be treated: for grain sizes larger than 500 µm, the path taken will be one of dry or wet screening, whilst for finer grain sizes, pneumatic classification or hydraulic classification are preferable.