PROCESS AND APPARATUS FOR EXTRACTING SOLUTES FROM THEIR AQUEOUS SOLUTIONS
Nickel and/or copper cations can be extracted, from their aqueous solutions also containing chelating agents, by liquid-liquid extraction with an organic solvent containing suitable complexing extractants for the nickel and/or copper. However, with the most efficient such complexing extractants, the phenolic ketoximes and aldoximes, the pH of the aqueous solutions to be extracted should be substantially more alkaline than those known in the prior art for extraction of solutions with about the same amounts of extractable metals but without chelating agents. Apparatus for carrying out the extraction process includes a tank for permanently containing an organic solvent, and a plurality of pumps and valves operable for transferring aqueous feed solution from a source thereof to the organic solvent tank, for mixing therewith, thereafter draining off the raffinate, followed by transferring regenerant solution into the organic solvent tank for regenerating the solvent, followed by draining off the used regenerant solution.