Scale-Up of Centrate Clarity Limiting Applications

Scaling up between two decanter sizes is generally best done when there is geometrical similarity between them. This means the same beach angle, the same conveyor pitch angle, and the same conveyor and feed zone designs. When there are differences then the scale-up may not be reliable. 

A centrate clarity limiting application is characterised by a fall off in centrate quality, when feed rate is increased, independent of conveyor differential, once pond depth has been optimised. Spent wash dewatering, discussed in the previous chapter, is one such example. 

To scale any of the capacities tested to another size of decanter, or the same decanter with a different bowl speed, the ratio of Sigma values simply would be used. 

The clay and lime classification applications, covered in Chapter 6, are also examples of data which would be scaled by Sigma ratios. 

The lowest capacity would achieve 90% recovery of calcium hydroxide, and the highest 85%. 

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