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

Abstract

The electrochemical performances of deposited MnO2 on lead alloy anode by pulse current (PC) and direct current (DC) electrodeposition in manganese sulfate solution were investigated by performing measurements of galvanostatic polarization, cyclic voltammetry (CV), and Tafel tests. The composition and morphology of MnO2 were observed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The anode deposited with MnO2 layers by PC electrodeposition presented a lower anodic potential of 60 mV and more uniform potential oscillating attractor with fractal dimension of 1.0337 compared with those of DC electrodeposition. In addition, MnO2 layers exhibited excellent corrosion resistance because less intermediate oxide Mn­(III) appeared in anode deposits. Furthermore, the cathodic current efficiency improved by 3.11∼3.77% and energy consumption decreased by 5.30∼8.17% after galvanostatic electrolysis for 2∼8 h by using PC instead of DC for manganese metal electrodeposition. As an external control method, PC electrodeposition not only regulated the structure and surface morphology of MnO2 but also affected the anode electrochemical behaviors and cathode manganese metal deposition. Electrochemical oscillations and other characteristics of anode reaction described in this study could inspire future work on promoting the whole electrowinning process.

Revealing the Reaction Mechanism of Lead Anodes in the Manganese Electrowinning Process

“…The core procedure of this method is the electrolysis of a neutral manganese sulfate solution. 3,4 In this process, manganese ions are reduced and deposited on the cathode made of stainless steel. At the same time, the oxygen evolution reaction (OER) occurs on the anode.…”

“…Manganese metal is a key raw material in basic chemical industries and the fourth most consumed metal in the world. , At present, the main production method of metal manganese is leaching-electrolysis. The core procedure of this method is the electrolysis of a neutral manganese sulfate solution. , In this process, manganese ions are reduced and deposited on the cathode made of stainless steel. At the same time, the oxygen evolution reaction (OER) occurs on the anode.…”

Contradictory role of reactive oxygen species in dissolution-dependent activity of Pb-based anodes in acidic electrooxidation

“…12 Pb-based anodes have been commercially used in the eld of electrodeposition of copper, zinc and manganese due to their low preparation costs and high conductivity. 13,14 However, the application of Pb-based anodes in the concentrated acid environment of the hydrometallurgical process is impeded by Pb corrosion and low OER activity during the electrooxidation process. 15 The high OER overpotential of anodes caused high energy consumption in the zinc electrowinning process.…”

“…Manganese dioxide (MnO 2 ), featuring environmental friendliness, acid stability and low costs, has been widely used as a precoating layer for Pb-based anodes. 14,15 However, ROS behaviour control is oen ignored in the research of Pb-based anode modication due to the lack of a deeper understanding of the ROS driven mechanism behind the Pb release process, a kinetically and thermodynamically favourable process for Pb corrosion and dissolution.…”

Ti/Ti4O7 Anodes for Efficient Electrodeposition of Manganese Metal and Anode Slime Generation Reduction

“…The oxygen evolution reaction (OER) is the main anodic reaction, and the side reaction is the electro-oxidation reaction to generate anode slime (mainly MnO 2 ). Owing to the relatively close potential of OER and MnO 2 deposition, it is difficult to avoid the side reaction of MnO 2 formation . Therefore, strict control of anode slime production is one of the important technical problems and indicators for high-quality development of the electrolytic manganese industry.…”