SX PLANTS

EW PLANTS

LEACHING

HYDROMET

COALESCERS

NOMENCLATURE FOR SOLVENT EXTRACTION

Aqueous Continuous: The condition when the organic phase is dispersed as small droplets throughout the aqueous phase.

Crud: A common term for the mass of solids that accumulate at the organic/aqueous interface.

Diluent: The organic solvent that the extractant is dissolved in to form the organic phase. It consists of either aliphatic or aromatic hydrocarbons, or a mixture of the two.

Dispersion: An unstable emulsion caused by contacting the organic and aqueous phases.

Distribution Coefficient: It is a measure of the extracting power of the organic phase. It equals the concentration of the metal in the organic phase divided by the concentration in the aqueous phase.

Distribution Curve: Also known as isotherm and McCabe-Thiele diagram. It is a plot showing the relationship, at equilibrium, between the concentration of the metal in the aqueous phase as a function of the metal in the organic phase.

Emulsion: It is a stable dispersion of the organic and aqueous phases that require a long time to coalesce and separate.

Extractant: The active component in the organic phase that chemically reacts with the metal to from an organic-metal complex that is soluble in the organic phase.

Entrainment: Is the suspension of small droplets of one phase that is carried away by another phase.

Extraction Kinetics: The rate at which a metal transfers from the aqueous phase to the organic phase. It determines the contact time and size of the mixer.

Loading Capacity: The maximum concentration of a metal in the organic phase under a given set of conditions.

Modifier: A component added to the organic phase, usually for preventing the formation of a third phase by increase the solubility of the organic-metal complex.

O/A Ratio: The quantity of organic phase divided by the quantity of aqueous phase.

Organic Continuous: The condition when the aqueous phase is dispersed as small droplets throughout the organic phase.

Percent Extraction: It is calculated by the following equation:
% ext’n = O/A x D / (1 + O/A x D) x 100 
“D” is the distribution coefficient.

Phase Continuity: The type of dispersion of the two phases; either aqueous or organic continuous.

Phase Disengagement: A term used to describe when the organic and aqueous phases coalesce and separated into two components.

Phase Inversion: A change in the dispersion from one phase continuity to the other.

Separation Factor: It is a measure of the selectivity of the organic phase. It is calculated by the following equation: 
SF=D_metal / D_impurity
“D” is the distribution coefficient.

Settler Area: A measurement to describe the required size for a settler. Usually expressed as m³/h/m²

Synergism: The effect of two or more extractants in the organic phase.

For information on solvent extraction technology, click on the following links:

Solvent Extraction Process Description

O/A Ratios and Phase Continuity on Entrainment

Download SX Nomenclature.pdf