Study On The Mechanism Of Electrode Process In The Electrolytic Manganese System

At present, manganese was mainly produced by electrolysis. After years ofdevelopment, there still were a lot of problems in the electrolytic manganese process,such as low current efficiency, producing great amount of by-products,environment-unfriendly additives. The reasons for these problems were that themechanism of additive at the cathode interface and the power consumption in the anodezone were not clear in the electrolytic manganese process. Therefore, investigating themechanism of electrode process in the electrolytic manganese system, which will guidethe production process of electrolytic manganese and help to provide new ideas forresearching on high-efficiency electrolysis method.In this study, We focused on the mechanism of electrode process in electrolyticmanganese system, developed a new method to investigate the mechanism of thetrace-amount SeO₂additive at the cathode interface, and established a new method todetect the trace Se（IV） in the manganese solution; used a new theoretical perspective toinvestigate the anodic process, discovered the phenomenon of electrochemicaloscillations at the positive electrode for the first time, and found which could resultextra power consumption. The main content of the dissertation are as follows:①The mechanism of the SeO₂additive at the cathode interface is investigated viaSquare Wave Voltammetry （SWV） and Linear Sweep Voltammetry （LSV） methods.α-MnSe was the only Mn-Se species formed on the surface of the cathode via XRD.During electrolytic manganese, there is electrochemical equilibrium among α-MnSe,Mn2+and Se （IV） species. The equilibrium could be regulated by varying the CMn2+andthe CSeO₂, through which the electrolytic manganese process could be improved.②A cathodic process analysis method was established via SWV. And we draw astandard curve, linear regression equation is ip（A）=1.4995C（mol/L）, correlationcoefficient is0.9989, the detection limit is1.0×10^-7. In practical electrolytic manganeseprocess, this method is very important significance for monitoring the concentration ofSe（IV）.③The phenomenon of electrochemical oscillations is found in the anode zoneduring the electrolytic manganese process by electrochemical methods for the first time,but the phenomenon is not observed in the cathode zone. The influence of the CMn2+,potential, temperature, pH and CSeO₂on the amplitude and the frequency are investigated. The SEM micrographs of oxide on the anode show that the oscillationsignal will be changed with the nano structure of the oxide on the anode during theelectrolytic manganese. The oscillation may result extra power consumption, whichcould be14%.