Selective Separation of Iron from Simulated Nickel Leach Solutions Using Ion Exchange Technology

The separation of Fe(III) from simulated Ni(II) solutions using different ion exchange resins was studied to improve nickel recovery in hydrometallurgical processes. The objective was to identify the most effective resin type and dosage for optimal iron separation. Various cation exchangers with sulfonic and carboxylic groups, along with chelating resins containing iminodiacetic, aminophosphonic, and mixed sulfonic and phosphonic groups, were tested. Resin dosages ranged from 0.1 to 0.5 g/mL to assess their impact on iron separation from solutions with 25 g/L of both Ni(II) and Fe(III) at pH 1.5. The research also explored the effects of metal ion concentration ratios, pH, and adsorption durations. Results indicated that all selected chelating resins favored the adsorption of Fe(III) over Ni(II), achieving a high Fe(III) loading. Soft cation exchange resins exhibited a preference for Fe(III) as well, but with less significant loading. In contrast, strong cation exchange resins did not show preferential adsorption. The aminophosphonic resin demonstrated the highest separation efficiency, achieving over 94% Fe(III) adsorption while keeping Ni(II) adsorption below 5%. This study provides insights into ion exchange separation technology for nickel purification.