Clarification Rate
also known as settling flux · settling velocity
The clarification rate, sometimes called the settling flux, is the volumetric overflow rate per unit of settling area. A particle is removed only if its settling velocity exceeds the upward liquid velocity, so the required settling area equals the overflow flow rate divided by the design settling velocity. For flocculated sludges the design velocity is determined by a settling test, not by Stokes' law.
Why it matters in practice
This single relationship sizes every clarifier, thickener and settler on the plant. On solvent extraction circuits the same reasoning sizes the settler — with the settling velocity replaced by the phase disengagement behaviour of the dispersion.
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Reference entry GL-CLARIFICATION-RATE. Definitions on this page describe engineering practice in hydrometallurgical process design; they are not a substitute for test work on your own material.