Abstract: Alternative equilibrium modifiers for use with aldoxime extractants, such as hydroxyl aryl aldoxime extractants, employed in the process for extraction of metal values, particularly copper values, in the extraction from aqueous solutions, in which the extractant and modifiers are employed in an organic solvent phase, the solvent being a water insoluble, water immiscible hydrocarbon solvent, such as a kerosene.

Abstract: An improved process for the extraction of a metal from an aqueous ammoniacal solution comprising: (i) contacting the aqueous ammoniacal solution with an extraction reagent comprised of a water insoluble extractant for the metal, to provide an organic phase, now containing metal values, and an aqueous phase from which metal values have been extracted; (ii) contacting the organic phase with an aqueous stripping solution to provide an aqueous strip phase, now containing metal values, and an organic phase from which metal values have been stripped; and (iii) recovering the metal values from the aqueous stripping solution; the improvement wherein (a) the extraction reagent contains an ammonia antagonist having only hydrogen bond acceptor properties; (b) the stripping solution is an aqueous highly acidic solution; and (c) the organic phase is washed with a weakly acidic aqueous solution prior to stripping with the highly acidic aqueous stripping solution.

Abstract: A process for the recovery of nickel from a nickel containing ore in which the ore, particularly a laterite ore, is initially leached with an aqueous acid solution, after which the nickel is precipitated as nickel hydroxide by adding a hydroxide to the aqueous acid leach solution containing the nickel, followed by a re-leaching of the nickel with an aqueous ammoniacal solution and recovery of the nickel by a solvent extraction of the nickel from the aqueous ammoniacal solution with an organic phase of a water insoluble oxime extractant dissolved in a water-immiscible hydrocarbon solvent and the nickel recovered by electrowinning the nickel from the aqueous acid stripping solution employed to strip the nickel from the organic phase.

Abstract: Toxic cyanide and anionic metal species are removed from aqueous alkaline solutions by contacting the aqueous alkaline solutions with an extractant compound which is capable of being protonated at a pH of 9 or above. Whereby the anionic metal species is extracted from the aqueous alkaline solution, subsequently stripping the metal values from the extractant and recovering the metal species, preferably by electrowinning. The process is useful in a flotation process in which a recycled aqueous process stream is employed in that the toxic cyanide ion and anionic metal species are removed prior to recycling of the aqueous process stream for flotation.

Abstract: An improved process is described for the recovery of copper from an aqueous feed solution using solvent extraction and electrowinning in which the electrowinning is conducted in a first step wherein the electrolyte is flowing perpendicular to the cathode surface without auxiliary mixing of the electrolyte between electrodes, and a second step wherein the electrolyte is flowing parallel to the cathode surface. In a second embodiment, solvent extraction of copper and solvent extraction of acid are conducted in alternate steps to allow more complete recovery of copper.