Distribution Coefficient
also known as D · distribution ratio · Kd
The distribution coefficient D is the concentration of metal in the organic phase divided by its concentration in the aqueous phase, both measured at equilibrium under stated conditions of pH, temperature, extractant concentration and O/A ratio. It is the single number that drives every stage calculation: the higher D is, the fewer theoretical stages a target recovery requires.
Why it matters in practice
D is measured in shake-out tests, one of the cheapest and most informative experiments in hydrometallurgy. Because D varies steeply with pH, reporting it without the pH it was measured at makes the number meaningless.
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Reference entry GL-DISTRIBUTION-COEFFICIENT. Definitions on this page describe engineering practice in hydrometallurgical process design; they are not a substitute for test work on your own material.