Study On The Mechanism And Controlling Strategies For The Anode Oscillation During Electrolytic Manganese Process

As an important additive of stainless steel,manganese metal is of great significance to the national economy.Manganese metal is mainly produced by hydrometallurgy.However,the production process still endures high energy consumption and large amount of by-product.In industry,the electrolysis process is in a high concentration,high current density and open-flow conditions,which is far from the equilibrium state.As the previous studies reported,nonlinear phenomena,such as electrochemical oscillation and fractal growth,were found in such electrolysis process.These nonlinear phenomena will be accompanied by extra electrolytic energy consumption.It is possible to develop new energy-saving technologies based on the study of the dynamics of these nonlinear phenomena.In the process of electrolytic manganese metal,the metal manganese is mainly produced by cathodic reduction,but the anode process also accounts for a large proportion in the overall energy consumption,the anode process is less concerned in previous studies,however.In this paper,we focus on the nonlinear dynamics mechanism of electrolytic manganese anode.The electrochemical behavior of the anode was investigated under constant current condition,and the relationship between the frequency and amplitude was analyzed.Then,by using the mathematical methods such as linear instability analysis,the anode dynamic equations are established under the condition of constant current.Finally,the influence of the pulse electrolysis conditions on the electrochemical oscillation behavior is studied.Try to provide new ideas for the development of new electrolytic technology.The contents and conclusion of the experiment were shown as followed:(1)The electrochemical behavior of the anode was investigated under constant current conditions.It is found that the main reason for the initiation of electrochemical oscillations is the autocatalytic effect of ?-MnO2 on the surface of the anode.The anode of different materials can produce obvious oscillation,that the frequency and amplitude are closely related to the factors such as electrolytic voltage,manganese ion concentration,temperature,pH value and so on.Under the condition of constant current electrolysis,the potential oscillation can lead to the decrease of energy consumption,and the energy consumption account for 11.57% of the total energy consumption.It is possible to further reduce the power consumption of non-ohmic effect in the electrolysis system by adjusting the anode potential oscillation under constant current condition.(2)The dynamic equations of the anode under constant current conditions are studied,and the cause of the potential oscillation and the threshold range are discussed.The results show that the dynamic rate parameters will change with the change of the electric potential under the condition of constant current,so that the nonlinear dynamic differential equations are different from the constant pressure conditions.Combined with linear instability analysis and Matlab operation,we discussed the theoretical relationship between the instability of the solution of the equations and the oscillatory behavior,and provided the threshold range of anode oscillation.The simulation results are in agreement with the experimental data,which proves the rationality of the mechanism.which provides the basis for the quantitative analysis of the dynamics of the oscillation mechanism.(3)The influence of external control pulse current electrolysis conditions on electrochemical self-oscillation was investigated.The results show that the average current density and the period of the external control pulses have a significant effect on the electrochemical self-oscillation of the anode.During the off time of a single current pulse,two discharge platforms appear at 1.0 V and 0.4 V,respectively.If the turn off time is too long,the potential will fall into the second discharge platform,and the concentration of the surface active intermediate will change,lead to self-oscillation recovery time delay.This study provides a theoretical basis for understanding the setting and optimization of pulse electrolysis parameters.This study enriches the understanding of the nonlinear behavior of the anode in the process of electrolytic manganese,and provides a new way to develop efficient electrolysis.