The principle of pelletization (also called granulation) is in opposition to that of grinding: it consists of assembling or agglomerating fine solid particles in order to form components with larger dimensions (spheres, briquettes or cylindrical pellets).

There are two main granulation methods:

  • granulation in wet mediums: the cohesion of the particles is obtained by means of the addition of a liquid binder (most frequently water but also molasses and lignosulfonate-type chemical agents) and the mechanical action of a suitable device (pelletization plate, mixer granulator, etc.). No compression is applied to ensure the firmness of the pellets;
  • granulation in dry sorting: the pellets are obtained by compression; their cohesion being thereby ensured by the combined effect of the reduction in the spacing of the particles and the increase of their contact surface. This granulation is carried out with or without a binder. Their operational modes are carried out by means of briquetting presses (iron ores, for example) or pelletizing presses with extruders (manufacturing of solid recovered fuels (SRF)).

The effectiveness of the operation is often contingent on the mechanical strength of the granules formed (crush test, attrition test, etc.)

The main advantages of pelletization are a densification of the material, which allows for a reduction of storage or transport costs, ensures easier handling of the material, or improves its flowability.

The CTP has a range of equipment of pilot size, such as a pelletization plate, an Eirich pelletizer or a pelleting press (Khal) in order to carry out tests, both on mineral materials and alternative fuels which are intrinsically plastic or organic.

Equipment Mode Capacity Format material IN Format pellets
Pelletization plate Batch/laboratory 1 kg/batch Mineral < 1 mm Round pellets 5-15 mm
Continuous/pilot 15-50 kg/h
EIRICH intensive mixer Batch/laboratory 5 l / 3-4 kg/batch Mineral Round pellets - max 10 mm with standard agitator - max 1 mm with special agitator
Batch/pilot 75 l / 70 kg/batch
Pellet press Continuous/pilot 50 - 200 kg/h soft (polymers, biomass, etc.) 10 - 35 mm Cylinder diameter 6 mm, lenght 20 mm

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