Patent ID: 8323596

Claim:
A method for extracting zinc from an aqueous ammoniacal zinc solution containing impurities, wherein: (i) contacting the aqueous ammoniacal zinc solution containing impurities with an organic phase comprising an ammonium salt of an organic extractant dissolved in a hydrophobic diluent, allowing transfer of the zinc to the organic phase and transfer of ammonium to the aqueous solution, thereby providing a zinc-enriched, ammonium-depleted organic phase and an ammonium-enriched, zinc-depleted aqueous phase containing impurities; (ii) separating the zinc-enriched, ammonium-depleted organic phase from the ammonium-enriched, zinc-depleted aqueous phase containing impurities; (iii) contacting the zinc-enriched, ammonium-depleted organic phase with an aqueous solution containing positively charged species, allowing transfer of the zinc from the organic phase and transfer of positively charged species from the aqueous phase, thereby providing an aqueous zinc solution and an organic phase containing a zinc-depleted organic extractant; and (iv) recovering the zinc from the aqueous zinc solution.