Sedimentation

Overview

When the sedimentation principle is used for granulometric analysis, it is using the fact that particles of different size have different velocities in a fluid at rest. Therefore, the temporal and spatial changes of concentration in a sedimenting system provide substantial information on the quantitative distribution of particle sizes characterized by the speed of their motion. The measurement of such distributions is called sedimentation analysis; it requires the theoretical understanding and experimental handling of the following two phenomena:

• 1. Connection between sedimentation velocity and particle size as a function of the material properties of the system and the other conditions in the sedimentation vessel (Chapter 3).

• 2. Connection between the concentration distribution of the solid observed after time t and its size distribution. This requires methods both indicating concentration changes and allowing us to calculate the distribution from the measured data.