Thickener-Basin Depth

Thickener-Basin Depth The pulp depth required in the thickener will be greatly affected by the role that compression plays in determining the rate of sedimentation. If the zone-settling conditions define the area needed, then depth of pulp will be unimportant and can be largely ignored, as the normal depth found in the thickener will be sufficient. On the other hand, with the compression zone controlling, depth of pulp will be significant, and it is essential to measure the sedimentation rate under these conditions. 

Three key parameters are required for thickener design the thickener basin area (or unit area), the thickener basin depth, and the torque for the rake. These are discussed here. 

Thickener Basin Depth. In the hindered settling conditions, the pulp depth is unimportant in the determination of thickening rate and can be omitted. As the pulp enters into the compression regime, the pulp depth and the agitation affect the thickening rate. In this case, the compression zone unit volume may be calculated from the equation (Perry et al., 1997)... 

To determine the compression-zone requirement in a thickener, a test should be run in a deep cylinder in which the average settling pulp depth approximates the depth anticipated in the full-scale basin. The average density of the pulp in compression is calculated and used in Eq. (18-47) to determine the required compression-zone volume ... 

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