Enhanced recovery of high-purity Fe powder from iron-rich electrolytic manganese residue by slurry electrolysis

Iron-rich electrolytic manganese residue (IREMR) is the industrial waste residue produced during the processing of electrolytic metal manganese, which contains amounts of Fe, Mn resources and other heavy metals. In this study, to recover high-purity Fe powder from IREMR, slurry electrolysis technique was used. The effects of the IREMR and H₂SO₄ mass ratio, current density, reaction temperature and electrolytic time on the leaching efficiency and current efficiency of Fe were studied. The results indicated that high-purity Fe powder can be recovered from the cathode plate and that the slurry electrolyte can be recycled. The leaching efficiency, current efficiency and the purity of Fe were 92.43%, 80.65% and 98.72%, respectively, when the mass ratio of H₂SO₄ and IREMR was 1:2.5, the reaction temperature was 60℃, the electric current density was 30 mA/cm², and the reaction time was 8 h. In addition, the VSM analysis showed that the coercivity of electrolytic iron powder was 54.5 A/m, which reached the electrical pure iron powder coercivity advanced magnetic grade (DT4A coercivity standard). The slurry electrolytic method provides fundamental support for the industrial application of Fe resource recovery in IRMER.