Removal of ferric ions from aluminum solutions by solvent extraction, part I: Iron removal

• Over 97% Fe was extracted from Al with a P204/N235 system in a single contact.
• Only 3% Al was co-extracted, indicating good separation of Fe from Al.
• Almost 99% Fe was stripped easily using 1 mol/L H2SO4.

This study investigated removal of ferric ions from aluminum solutions to explore the basic data for the recovery of aluminum resources from coal spoil. A novel synergic extractant, consisting of di-(2-ethylhexyl) phosphoric acid (P204) and tertiary amine (N235) with sulfonated kerosene (SK) as diluent, was adopted in this research. The influences of reaction time, pH, temperature, and phase ratio, on the extraction processes were systematically investigated. Result showed the Fe removal was greater than 97% in only one contact under optimal conditions. The corresponding stripping processes were also performed focusing on the effects of phase ratio, H2SO4 concentration, and reaction time. Almost 99% Fe was easily stripped using 1 mol/L H2SO4. These findings indicated that compared with single extractants, the new synergic extractant shows significant advantages.