Promotion of manganese extraction and flue gas desulfurization with manganese ore by iron in the anodic solution of electrolytic manganese

Abstract

In this work, Mn ore was mixed with the wastewater anode solution of electrolytic Mn (ASEM, instead of water) and utilized as the desulfurizer for simultaneous SO2 removal from flue gas and Mn extraction. The effects of Fe2+ and Fe3+ on Mn leaching and flue gas desulfurization were investigated. For MnO2 and Mn2O3 (mixed with ASEM), the introduction of Fe2+could simultaneously increase Mn extraction efficiency and flue gas desulfurization efficiency when MnO2 and Mn2O3 mixed with ASEM was used. Fe3+ addition could improve desulfurization efficiency obviously for MnCO3. Fe2+ could react with MnO2 and H+ to form Mn2+ and Fe3+. This reaction further improved Mn extraction and simultaneously decreased the acidity of ASEM, thus promoting SO2 removal. The introduced Fe3+ could react with SO2, when MnO2 was absent from the desulfurizer slurry. The resulting Fe2+ was then oxidized by O2 to form Fe3+, which underwent a Fe3+ ↔ Fe2+ cycle to promote flue gas desulfurization. Thus, the introduction of Fe ions, especially Fe2+, could promote simultaneous Mn leaching and flue gas desulfurization with Mn ore. This work provided not only a new way for effective SO2 removal from flue gas and Mn extraction but also for recycling ASEM.