Enhanced extraction of manganese from electrolytic manganese residue by electrochemical

•Electric field was used to strengthen extraction of high-valent manganese.•The mechanism of electrochemical leaching process was explored.•The optimal conditions for manganese extraction were determined.•The extraction efficiency of manganese reached 96.2% under the optimum conditions.

High-valent manganese was hard to be extracted from electrolytic manganese residues. To strengthen the extraction of Mn, electrochemical extraction method was investigated in this work. The mechanisms of the electrochemical extraction were examined along with the electrochemical performance of the reaction system via X-ray diffraction, scanning electron microscopy, X-ray Fluorescence, and BET. Results show that high-valent manganese can be reduced effectively under an electric field. The extraction efficiencyof manganese reached 96.2% under the optimum conditions of current density 25 mA/cm2, 9.2 wt% H2SO4, solid-to-liquid ratio of 1:5, room temperature, 1:1.0 M ratio of Mn to Fe2 + and 60 min extraction. The extraction efficiency of manganese is 51.8% higher than that attained under the same conditions without an electric field and Fe2 +. Meanwhile, the manganese content in residue decreased from 2.34% to 0.09%.

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