Solvent extraction processes for metal recovery

In a solvent extraction process for the recovery of copper from an aqueous feedstock containing copper and iron values wherein the aqueous feedstock is contacted with an organic phase comprising a reagent composition including an extractant and in which a copper loaded organic phase is provided by extraction of said copper values from said aqueous feedstock and wherein contact between the aqueous feedstock and the organic phase is accomplished by means of at least one mixer-settler extraction stage and at least one strip stage to provide a pregnant copper electrolyte from which the copper is electrowon in an electrowinning stage to provide cathode copper and stripped electrolyte, the improvement comprising washing said copper loaded organic phase in a wash stage prior to stripping said copper values therefrom with an aqueous acidic wash solution that has been contacted with copper metal prior to washing the copper loaded organic phase, and wherein contact between the aqueous acidic wash solution and the copper metal is achieved by adding the copper metal to a settler in the wash stage or to an overflow weir in the wash stage.

In a solvent extraction process for the recovery of copper from an aqueous feedstock containing copper and iron values wherein the aqueous feedstock is contacted with an organic phase comprising a reagent composition including an extractant and in which a copper loaded organic phase is provided by extraction of said copper values from said aqueous feedstock and wherein contact between the aqueous feedstock and the organic phase is accomplished by means of at least one mixer-settler extraction stage and at least one strip stage to provide a pregnant copper electrolyte from which the copper is electrowon in an electrowinning stage to provide cathode copper and stripped electrolyte, the improvement comprising washing said copper loaded organic phase in a wash stage prior to stripping said copper values therefrom with an aqueous acidic wash solution that has been contacted with copper metal prior to washing the copper loaded organic phase;

• wherein the wash stage comprises a mixer, a settler, and an aqueous recycle line leading from the settler to the mixer, and contact with the copper metal is achieved by placing the copper metal inside a container which is mounted in said aqueous recycle line.

In a solvent extraction process for the recovery of copper from an aqueous feedstock containing copper and iron values wherein the aqueous feedstock is contacted with an organic phase comprising a reagent composition including an extractant and in which a copper loaded organic phase is provided by extraction of said copper values from said aqueous feedstock and wherein contact between the aqueous feedstock and the organic phase is accomplished by means of at least one mixer-settler extraction stage and at least one strip stage to provide a pregnant copper electrolyte from which the copper is electrowon in an electrowinning stage to provide cathode copper and stripped electrolyte, the improvement comprising washing said copper loaded organic phase in a wash stage prior to stripping said copper values therefrom with an aqueous acidic wash solution that has been contacted with copper metal prior to washing the copper loaded organic phase;

• wherein contact with the copper metal is achieved by pretreatment of the aqueous acidic wash solution with the copper metal prior to sending it to the wash stage by using an electrowinning cell containing a copper coated cathode in which catholyte and anolyte are separated from each other by a semipermeable membrane, and wherein the anolyte is water and the catholyte is the aqueous acidic wash solution.