电冶金过程中熔融FeO中离子电化学输运模拟研究

NUMERICAL STUDY ON ELECTROCHEMICAL TRANSPORT OF IONS IN THE MOLTEN FeO DURING ELECTROMETALLURGY

介绍了在离子输运和电化学反应理论基础上,建立了二元对称电解质FeO电化学输运的数值模型,模型包括两个平行平板电极和熔融FeO电解质。采用有限体积法对无量纲Poisson-Nernst-Planck方程和非线性Butler-Volmer方程进行求解,模拟离子的电迁移和扩散行为。同时分析了稳态电解质内的离子浓度、电荷密度和电势的变化。研究表明:受外加电压的影响,O2-向阳极迁移。Fe^(2+)因参与法拉第反应,在阴极积累。当外加电压分别为0.1 V、0.2 V、0.3 V时,X=0.05 mm处的电势分别为-0.029 V、-0.016 V、-0.006 V。随着外加电压的增大,电极附近的电势梯度逐渐增大,阴极和阳极电荷密度差值也逐渐增大。

Based on the theory of ion transport and electrochemical reaction,the paper presents a numerical model on electrochemical transport of ions.The model consists of two parallel electrolytes and melting electrolyte(FeO).Aiming to simulate the electromigration and diffusion behavior of ions,the dimensionless Poisson-Nernst-Planck(PNP)equations and non-linear Butler-Volmer equations are solved by the Finite Volume Method(FVM).Meanwhile,the concentration variation of ions,charge density and electric potential are analyzed at a steady state.The results show that O2-migrates to the anode due to the influence of applied voltage.Ferrous ion(Fe^(2+))accumulates at the cathode since its participation in Faraday reaction.When the applied voltage is of 0.1 V,0.2 V and 0.3 V,the potential is-0.029 V,-0.016 V,-0.006 V at X=0.05 mm,respectively.With the increase of applied voltage,The potential gradient increases gradually near the electrode.And the difference of charge density between cathode and anode also increases gradually.