Nd(III)在NaF-KF熔盐钨电极上电化学行为

Electrochemical behavior of Nd (III) on tungsten electrode in NaF-KF molten salt

  • 摘要: 钕铁硼磁体中稀土元素钕占据较大比重,从钕铁硼废料回收稀土有重大意义。为进一步了解钕在高温下氟化物熔盐的行为,本文在1 063 K采用NaF-KF(摩尔比2:3)电解质体系,加入质量分数为1%的NdF3,以Pt为参比电极,钨棒为对电极,用循环伏安法等电化学暂态测试研究了Nd(III)在惰性钨电极上的电化学过程,探究Nd(III)的还原机理。结果显示:Nd(III)于NaF-KF-NdF3熔盐中在惰性钨电极上的电化学还原过程是受扩散控制的不可逆的一步反应:Nd(III)+3e-=Nd,1 063 K时循环伏安法得到Nd(III)的扩散系数为2.107×10-5 cm2/s,钕的成核机制为瞬时成核。

     

    Abstract: The rare earth element neodymium accounts for such a large proportion in NdFeB magnets that it is of great significance to recycle rare earth from NdFeB waste. In order to further understand the behavior of neodymium in fluoride molten salt at high temperature, NaF-KF(molar ratio 2:3) electrolyte system was used at 1 063 K, and 1% NdF3 was added, with Pt used as reference electrode and tungsten rod as counter electrode. The electrochemical process of Nd (III) on inert tungsten electrode was studied by cyclic voltammetry and other electrochemical transient tests to explore its reduction. It was found that the electrochemical reduction of Nd (III) on inert tungsten electrode in NaCl-KCl-NdF3 molten salt was an irreversible one-step reaction controlled by diffusion: Nd (III)+3e- =Nd, the diffusion coefficient of Nd(III) was 2.107×10-5 cm2/s by cyclic voltammetry and the nucleation mechanism of neodymium was instantaneous nucleation at 1063 K.

     

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