Abstract: The recovery of nickel from aqueous ammoniacal solutions containing nickel values by extraction of the nickel values therefrom with an organic solution containing an oxime extractant and an equilibrium modifier followed by stripping of the nickel values from the organic solution by a concentrated aqueous ammoniacal solution from which the nickel can then be recovered. The use of the equilibrium modifier and the concentrated ammonia stripping solution provides advantages in that (1) there is an increase in the nickel transfer of the reagent, (2) the strip solution can be built to a higher nickel concentration giving a lower volume nickel containing solution for further processing and (3) a lesser number of stripping stages are required.

Abstract: An improved extraction system employing a quaternary amine to extract anions from an aqueous solution, particularly precious metals such as gold or silver from an aqueous alkaline solution. The improvement comprises the use of a weak organic acid (a compound providing an acidic proton) along with the quaternary amine. The improvement is useful in both liquid-liquid and liquid-solid extraction systems.

Abstract: An improvement is disclosed in the solvent extraction process for recovering metal values, i.e. copper, from aqueous solutions, particularly aqueous solutions, containing copper and iron which may also include chloride, and more particularly to an improvement which provides for increased copper to iron ratios in the loaded organic extractant phase. The improvement comprises washing the loaded organic extractant phase prior to stripping of the copper values therefrom with an aqueous acidic scrub solution containing at least a portion of electrolyte.

Abstract: Improved solvent extraction processes for recovery of copper values from aqueous solutions which also contain dissolved iron values. In continuous, multiple stage, solvent extraction circuits, the overall copper/iron selectivity of reagents including hydroxy oxime extractants is enhanced by providing non-uniform residence times for aqueous feedstocks in extraction stages, i.e., longer effective residence times for the feedstocks in one or more initial extraction stages of contact with the reagent than in subsequent stages of contact with the reagent.

Abstract: Reagents formulated by admixture of selected hydroxy aryl ketoxime and hydroxy aryl aldoxime extractants provide for efficient recovery of metal values, especially copper values, by solvent extraction processes. Specified kinetic and equilibrium conditions, which would require use of predetermined quantities of kinetic additives if ketoximes alone were employed or predetermined quantities of equilibrium modifiers if aldoximes were employed, are secured through formulation of reagents including both ketoxime and aldoxime extractants with less than the predetermined quantities of kinetic additive or equilibrium modifier. Reagents employed in methods of the invention may include from 0 to about 20 mole percent of a kinetic additive based on ketoxime content and also optionally a modifier of extraction and stripping equilibria in an amount providing a degree of modification of the aldoxime constituent of from about 0.75 to 1.0 and preferably from about 0.90 to 1.0.

Abstract: Reagents formulated by admixture of selected hydroxy aryl ketoxime and hydroxyl aryl aldoxime extractants provide for efficient recovery of metal values, especially copper values, by solvent extraction processes. Specified kinetic and equilibrium conditions, which would require use of predetermined quantities of kinetic additives if ketoximes alone were employed or predetermined quantities of equilibrium modifiers if aldoximes were employed, are secured through formulation of reagents including both ketoxime and aldoxime extractants with less than the predetermined quantities of kinetic additive or equilibrium modifier. Reagents employed in methods of the invention may include from 0 to about 20 mole percent of a kinetic additive based on ketoxime content and also optionally a modifier of extraction and stripping equilibria in an amount providing a degree of modification of the aldoxime constituent of from about 0.75 to 1.0 and preferably from about 0.90 to 1.0.