Abstract: A hydrometallurgical solvent extraction method includes mixing an aqueous metal ion solution with an organic solution of metal extraction reagent to form a mixture, and allowing the aqueous metal ion solution and organic solution to phase separate from the mixture; wherein prior to mixing the aqueous metal ion solution and the organic solution, a water-soluble or water-dispersible polymer comprising pendant sulfonic acid or sulfonate salt groups selected from the group consisting of sulfonated polystyrene; an addition polymer including at least one of styrene-4-sulfonic acid and 2-acrylamido-2-methylpropane sulfonic acid; naphthalene sulfonic acid-formaldehyde condensate; lignosulfonate; salts thereof; and mixtures thereof, is added to the aqueous metal ion solution, the organic solution, or to both the aqueous metal ion solution and the organic solution.

Abstract: The invention relates to an aliphatic-aromatic heterocyclic compound A which comprises at least two heterocyclic rings B and C, to a metal extractant composition E comprising this aliphatic-aromatic heterocyclic compound A and an organic acid D having at least one carboxylic, sulfonic, sulfuric, phosphinic, phosphonic, or phosphoric acid group, and to a process to extract one or more metals M selected from the group consisting of Ni and Co from an aqueous acidic leach solution PL comprising ions of at least one of the metals M, and further, at least one kind of further ions selected from the group consisting of Fe ions, Al ions, Cu ions, Mg ions, Mn ions, and also silicate anions, by mixing the solution PL with an extractant composition E, separating the organic and aqueous phases, and recovering the metal M from the separated organic phase.