Decantation & filtration

The techniques of mineral processing  very often make use of operations working in wet sorting where the material is treated in the form of ‘pulp’ (slurry). It is necessary at different stages or at the end of the processing to separate the liquid phase from the solids.

This operation is carried out over two stages, in other words:

• Thickening, which employs decanting basins and sedimentation tanks (circular, lamellar, settling lagoon, etc.), with or without flocculating/coagulating agents, and which enables the gravitational concentration of the solid material into a far denser phase than the original pulp, with an initial separation of the liquid phase.
• Filtration, which employs the forced passing of the liquid phase through a porous material (canvas) which retains the solids, either by pressure (filter press) or by vacuum suction (belt filter press or drum filter).

Supplementary techniques meet the needs of more specific cases such as centrifuging ultrafine materials.

In terms of thickening, the CTP has the capacity to study the decantation parameters of a pulp in the laboratory (sedimentation curve, Talmage and Fitch method) as well as selecting the most appropriate flocculating agents, with the possible assistance of the manufacturers. As far as filtration is concerned, the CTP has laboratory filters thanks to which it also studies essential parameters such as filtration time, filtration capacity, etc.).

At the pilot level, the CTP’s test floors have available belt filter presses, vacuum belt filter presses and vacuum drum filters, of different dimensions and capacities. This equipment can be tested in accordance with the characteristics of the material, the applications and goals aimed for.