Even the basic material properties of a suspension are therefore of utmost importance for filtration properties. The following two examples describe the fundamental difference between mineral and organic particles in filtration. These examples also represent the respective endpoints of the practical range of mixtures to be filtered.

MINERAL PARTICLES

As the following graph shows, mineral particles represent the one of the easier filtration tasks. However, it must be taken into account that even here the slight modification of the particle size or particle size distribution changes the filtration properties.

As a rule, the following properties are to be emphasised in the filtration of mineral particles:

• • non-compressible

• • good drainage

• • high filtrate flow

The structure of mineral particles on the filter cloth shown allows an almost ideal filtration.

ORGANIC PARTICLES

In contrast to mineral particles, the filtration behaviour of organic particles can be described as poor. Their properties and high binding forces counteract filtration. Without additional measures, it is often not possible to get good filtration results.

Generally, the following properties are to be emphasised in the filtration of organic particles:

• • compressible

• • poor drainage

• • low filtrate flow

As a result, rapid pressure build-up and low throughput are to be expected with purely organic suspensions.