Efficient green separation of Fe-Mn magnetics in manganese sulfate residue via Mn morphology control

The long-term accumulation of manganese sulfate residues can lead to the release of soluble manganese ions, thereby contaminating the surrounding environment. Although numerous methods exist to address the issue of soluble manganese ions, current harmless treatment approaches fail to consider the subsequent utilization of manganese slag. This study aims to control the magnetic properties of processed residues by adjusting the addition of barium hydroxide and the reaction duration. Our results reveal that the harmless treatment of manganese sulfate slag is achievable with various amounts of barium hydroxide, and the magnetic properties of the reconstructed slag increase with the increased barium hydroxide dosage. Magnetic separation is employed to separate the magnetic components from the reconstructed slag, and the distribution state of these magnetic substance is modulated by altering the particle size and reagent addition. Under optimal conditions, this study finds that the grade of iron was 24.17 %, the grade of manganese was 8.08 %, and the recovery could reach 79 % for iron and 70 % for manganese. Finally, the fining slag obtained by magnetic separation was utilized as an additive in the preparation of ferrites, reducing the minimum reflection loss of the ferrites to −16.18 dB, signifying up to 90 % electromagnetic wave attenuation. These findings indicate that the fining slags holds great potential as a dopant for ferrites, offering a viable pathway for the resourceful and environmentally friendly treatment of manganese sulfate residues.