Cvetković Vesna S, Petrović Nataša M, Prasakti Laras, Feldhaus Dominic, Stopic Srecko R, Friedrich Bernd, Jovićević Jovan N
Institute of Chemistry, Technology and Metallurgy, National Institute of the Republic of Serbia, University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia.
IME Process Metallurgy and Metal Recycling, Institute of RWTH Aachen University, Intzestrasse 3, 52056 Aachen, Germany.
Materials (Basel). 2025 Jan 4;18(1):184. doi: 10.3390/ma18010184.
In situ measurements of the chemical identity and quantity of anode gases during electrochemical measurements and rare earth (RE) electrolysis from fluoride-based molten salts composed of different kinds of rare earth oxides (REOs) were performed using FTIR spectrometry. Linear sweep voltammetry (LSV) was carried out to characterize oxidation processes and determine the anodic effect from NdF + PrF + LiF + REO melt. RE complex formation and subsequent reactions on the GC anode surface were discussed to understand the formation pathways of CO/CO and perfluorocarbon gases (PFC), mainly CF and CF. The LSV shows that increasing the REO content from 1 wt.% up to 4 wt.% in the system, leads to a positive shift in the critical potential for a full anode effect, recorded around 4.50 V vs. W with 4 wt.% REO. The FTIR results from on-line off-gas analysis during LSV measurements indicate that the anode gas products were composed mainly of CO and CO, whereas CF can be detected before the full anode effect and CF at and after this phenomenon. Compositions of off-gases from electrolysis performed using different kinds of REOs were compared. The main off-gas component was found to be CO in RE electrolysis with REOs as raw materials, while in electrolysis with magnet recycling derived oxides (MRDOs), CO content was slightly higher compared to CO. PFC emissions during RE electrolysis were generally similar: CF was detected periodically, but in negligible concentrations, while CF was not detected.
在电化学测量以及由不同种类稀土氧化物（REO）组成的氟化物基熔盐进行稀土（RE）电解过程中，使用傅里叶变换红外光谱法（FTIR）对阳极气体的化学组成和数量进行了原位测量。采用线性扫描伏安法（LSV）来表征氧化过程，并确定NdF + PrF + LiF + REO熔体的阳极效应。讨论了稀土配合物的形成以及在气相色谱（GC）阳极表面的后续反应，以了解CO/CO和全氟碳气体（PFC）（主要是CF和CF）的形成途径。LSV表明，在该体系中，将REO含量从1 wt.%增加到4 wt.%，会使记录的全阳极效应临界电位正向移动，在REO含量为4 wt.%时，相对于钨（W）约为4.50 V。LSV测量期间在线尾气分析的FTIR结果表明，阳极气体产物主要由CO和CO组成，而在全阳极效应之前可检测到CF，在此现象发生时及之后可检测到CF。比较了使用不同种类REO进行电解时的尾气组成。发现以REO为原料的RE电解中，主要尾气成分是CO，而在使用磁体回收衍生氧化物（MRDO）进行的电解中，CO含量比CO略高。RE电解过程中的PFC排放总体相似：定期检测到CF，但浓度可忽略不计，而未检测到CF。
