Selective recovery of manganese from electrolytic manganese residue by using water as extractant under mechanochemical ball grinding: Mechanism and kinetics

Natural Pyrite-assisted Mechanochemical Recovery of Insoluble Manganese from Electrolytic Manganese Residue: Kinetics and Mechanisms

“…This finding meant that all soluble manganese was leached during low-speed ball milling leaching, whereas most of the MnO 2 was converted after high-speed ball milling with pyrite, verifying the effect of high-speed ball milling on the activation of pyrite and the reductive leaching of Mn(IV)-containing minerals. 17 For the fitting results of the Fe 2p XPS spectrum (Figure 4b), Fe existed in the form of Fe(II)−S (706.98), jarosite state Fe(III)−SO 4 (711.78 eV), Fe(III) (711.78 eV), and Fe(III) (719.70 eV) in the raw EMR, 50,51 and the percentage of these forms in EMR accounted for 1.85, 58.29, 23.71, and 16.15% of the total manganese content, respectively (Table S3). With the addition of pyrite, the amount of Fe(II)−S species increased to 10.90% and this content would decreased to 1.09% after the ball milling process at 500 rpm due to the high speed of rotation promoting mechanochemical reactions.…”

“…12 In view of the circular economy, therefore, it is essential to develop emerging resource recovery technologies of EMR toward improving the utilization efficiency of valuable manganese in the residue to realize the clean production of the EMM. 13 To date, numerous methods have been applied to leaching and extracting manganese from EMR, including water leaching, 14,15 acid leaching, 16,17 bioleaching, 18,19 and electrochemical leaching. 20,21 Water leaching is commonly applied in industries due to its simplicity and low cost.…”

Simultaneous Recovery of NH3–N and Removal of Heavy Metals from Manganese Residue Leachate Using an Electrodialysis System

“…4 Currently, the MR in China is mainly exposed in the open, which could cause huge pressure on the storage space and seriously endanger the ecological environment around the yard. 5 With the help of rain wash, the NH 3 −N and heavy metals would migrate into the surrounding water and soil in the form of manganese residue leachate (MRL). 4−6 The NH 3 −N in MRL will cause eutrophication and then break the balance of the aquatic ecosystem.…”

“…Manganese, one of the most strategic metals in the world, is always in high demand. , China is one of the largest countries of production, consumption, and export for electrolytic metal manganese. , However, manganese residue (MR), as the most contributing pollutant during the manganese production process, is not widely managed . Currently, the MR in China is mainly exposed in the open, which could cause huge pressure on the storage space and seriously endanger the ecological environment around the yard . With the help of rain wash, the NH 3 –N and heavy metals would migrate into the surrounding water and soil in the form of manganese residue leachate (MRL). − The NH 3 –N in MRL will cause eutrophication and then break the balance of the aquatic ecosystem. − Moreover, the heavy metals (Mn, Co, Pb; see Table S1 in the SI) can seriously threaten human health. − As a result, it is crucial to create technological solutions that are both effective and affordable to address pollution, which is caused by NH 3 –N and heavy metals in MRL.…”

Migration and Transformation Behavior of Mn2+ and NH4+-N in Electrolytic Manganese Residue at Different Leaching pH Environments: Release Kinetic Model, Physical Phase Changes, and Formation of Manganese Oxide

“…EMR is currently disposed of mainly through direct landfills, whose primary purpose is to prevent Mn 2+ , NH 4 + -N, and heavy metals from entering the environment. − Resource utilization is necessary to solve the pollution problems of EMR. There are still problems in the current EMR resource utilization process, such as the difficulty of completely removing Mn 2+ and NH 4 + -N, heavy metal pollution, low added-value products, low dosing of EMR, and secondary pollution of NH 4 + -N. − Due to changes in the fundamental physical properties of the EMR during the stockpiling process, Mn 2+ and NH 4 + -N are difficult to remove because of the formation of insoluble complex salts during the storage of EMR. However, no fundamental studies on the migration and transformation behaviors of Mn 2+ and NH 4 + -N during EMR storage have been reported in China and abroad.…”