Abstract: A method of extracting copper from an aqueous ammoniacal leach solution which is derived from the leaching of copper dross and which contains impurity cations, comprising contacting the leach solution with a copper-selective organic phase to take copper into the organic phase and then stripping the copper from the organic phase into an aqueous phase, the organic phase being washed with a dilute acid before stripping, wherein before the organic phase is washed with the dilute acid the concentration of copper in the organic phase is reduced below a level at which poor phase separation occurs under acid conditions.