The Electrochemical Performance and Reaction Mechanism of Coated Titanium Anodes for Manganese Electrowinning

Abstract

In this paper, electrochemical performance of coated titanium anodes in the manganese electrowinning process are investigated. The turbid anolyte can be avoid by using coated titanium anodes compared to conventional Pb anodes, and the generation of manganese dioxide (MnO 2 ) on anode can be also reduced. The deposited manganese dioxide layer on coated titanium anodes are uniform and compact after electrolysis by using Scanning electron microscopy (SEM), which is totally different from that on Pb anodes. The possible mechanism involving permanganate ion is proposed and confirmed by Square wave voltammetry (SWV) and in-situ ultraviolet-visible spectrophotometry (UV-VIS). Moreover, the cell voltage for coated titanium anodes is about 270 mV lower than that of traditional Pb anodes, exhibiting well energy saving effect. Linear sweep voltammetry and Tafel curves show that coated titanium anodes have lower Tafel slope and possess a better catalytic property for oxygen evolution reaction. Finally X-ray photoelectron spectroscopy (XPS) analysis manifests the Ru element can be oxidized to a higher valence state and has a blocking effect for active oxygen. Our results here offer some basic electrochemical data for the anode in electrolytic manganese system, and provide a promising path for replacing Pb anodes in electrolytic manganese industry.

Electrochemical Behaviors of MnO2 on Lead Alloy Anode during Pulse Electrodeposition for Efficient Manganese Electrowinning

“…15 Statistically, every ton of electrolytic manganese produced is inevitably accompanied by about 6∼9 tons of the solid waste and 50∼80 kg of MnO 2 as anode mud in practical industry production. 12,16 However, in some instances, MnO 2 deposits play an important role in anode protection such as impeding anode degradation and corrosion. Therefore, the study of electrochemical behaviors of MnO 2 and the corresponding anode reaction mechanism plays a key role in improving anode performance and reducing electrolytic energy consumption for the sustainable industrial application.…”

“…The oxygen evolution reaction (OER) is the main reaction on the lead alloy anode, and the oxygen overpotential is rather high, thus increasing the cell voltage and decreasing energy efficiency . Simultaneously, Mn 2+ is oxidized to form MnO 2 as the side reaction, which is inevitable because it has an electrochemical potential close to that of OER . The formation of MnO 2 changes the anode stability, and the underlying lead dissolution of anode contaminates the cathode product. , Moreover, the constant formation of anodic MnO 2 deposits and cell mud reduces electrolytic efficiency and may lead to anode/cathode short-circuits in the electrolysis process .…”

“…The formation of MnO 2 changes the anode stability, and the underlying lead dissolution of anode contaminates the cathode product. , Moreover, the constant formation of anodic MnO 2 deposits and cell mud reduces electrolytic efficiency and may lead to anode/cathode short-circuits in the electrolysis process . Statistically, every ton of electrolytic manganese produced is inevitably accompanied by about 6∼9 tons of the solid waste and 50∼80 kg of MnO 2 as anode mud in practical industry production. , However, in some instances, MnO 2 deposits play an important role in anode protection such as impeding anode degradation and corrosion. Therefore, the study of electrochemical behaviors of MnO 2 and the corresponding anode reaction mechanism plays a key role in improving anode performance and reducing electrolytic energy consumption for the sustainable industrial application.…”

Encouraging Voltage Stability upon Long Cycling of Li-Rich Mn-Based Cathode Materials by Ta–Mo Dual Doping

“…The c -axis of LRO-TM-2 increases, which could be ascribed to that Mn 4+ is reduced to Mn 3+ when highly valence ions (Mo 6+ ) induce the rebalance of charge (Table ). ,, …”

“…The c-axis of LRO-TM-2 increases, which could be ascribed to that Mn 4+ is reduced to Mn 3+ when highly valence ions (Mo 6+ ) induce the rebalance of charge (Table 2). 17, 23,24 ), so M-O restrains the releasing lattice oxygen upon the heat treatment process. 15,27−29 The value of c can reflect the size of the slab thickness (S(MO 2 )) and interslab space thickness (I(LiO 2 )), which are calculated according to the following formulas.…”