Extraction Isotherm
also known as loading isotherm · McCabe-Thiele data
An extraction isotherm is built by contacting a fixed organic composition with aqueous solutions of increasing metal concentration until equilibrium, then plotting organic loading against aqueous concentration. The resulting curve rises steeply at low concentration (high D), flattens as the extractant saturates, and terminates at the organic's maximum loading capacity.
Why it matters in practice
The isotherm is the raw material for stage calculations. Its plateau defines the practical upper limit of organic loading, and designing beyond that plateau is the most common cause of a circuit that under-performs at full scale despite good bench results.
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Reference entry GL-EXTRACTION-ISOTHERM. Definitions on this page describe engineering practice in hydrometallurgical process design; they are not a substitute for test work on your own material.