Selective removal of iron(III) from highly salted chloride acidic solutions by solvent extraction using di(2-ethylhexyl) phosphate

Metal ions including Fe3+, Ca2+, Mg2+, Ni2+, Co(2+)and Cu(2+)are commonly found in the leaching solution of laterite-nickel ores, and the pre-removal of Fe(3+)is extremely important for the recovery of nickel and cobalt. Di(2-ethylhexyl)phosphate acid (D2EHPA) showed high extraction rate and selectivity of Fe(3+)over other metal ions. The acidity of the aqueous solution is crucial to the extraction of Fe3+, and the stoichiometry ratio between Fe(3+)and the extractant is 0.86:1.54. The enthalpy for the extraction of Fe(3+)using D2EHPA was 19.50 kJ/mol. The extraction of Fe(3+)was > 99% under the optimized conditions after a three-stage solvent extraction process. The iron stripping effects of different reagents showed an order of H2C2O4> NH4HCO3> HCl > NaCl > NaHCO3> Na2SO3. The stripping of Fe was > 99% under the optimized conditions using H(2)C(2)O(4)as a stripping reagent.

Automated summary

Metal ion removal, especially Fe(3+), is crucial for the recovery of nickel and cobalt in the leaching solution of laterite-nickel ores. D2EHPA exhibits high extraction rate and selectivity for Fe(3+), with an extraction efficiency of over 99% under optimized conditions after a three-stage solvent extraction process. Different stripping reagents have varying effects on iron removal, with H(2)C(2)O(4) being the most effective in achieving over 99% iron stripping efficiency under the optimized conditions.