Study on Iron-nickel Separation Using Ion Exchange Resins with Different Functional Groups for Potential Iron Sub-production

Abstract

ABSTRACT This research study reviews a direct comparison of the loading capabilities and selectivity of 13 different ion exchange resins represented in 24 different commercial resins for the removal of Fe(III) from synthetic Ni(II) leach liquor. The use of ion-exchange resins for selectively removing high concentrations of Fe(III) from leach liquor is presented as an alternative to current Fe precipitation processes in base metal industry. Our results show that resins with aminophosphonic, iminodiacetic, a combination of phosphonic-sulfonic groups, and methyl-glucamine groups favored the Fe(III) loading over Ni(II) and obtained high percentage of metal loadings. Resins with carboxylic, amidoxime, phosphoric, and phosphinic acid groups also favored the Fe(III) loading but achieved low percentage of metal loadings. Resins with active sulfur groups containing thiourea, isothiouronium, and thiol showed compromised adsorption preferences to Fe(III), and achieved low percentage of metal loadings. Sulfonic groups showed no adsorption preferences for Fe(III) but achieved relatively high metal loadings. Contrarily, bis-picolylamine groups showed preferences for Ni(II) loading. Our results suggest that resins with methyl-glucamine and amidoxime groups have the best potential to achieve successful Fe(III) removals. Thus, the recovery of high concentrations of Fe(III) at similar Ni(II) concentrations by ion exchange resins is confirmed at laboratory scale supporting its potential to replace precipitation in the base metal purification process. Further technical and economic studies for the development and scale-up process are still required to confirm its industrial application.