In this century, our daily life is surrounded by technological devices, and Rare Earth Elements (REE) are at the heart of this technological revolution. They are always listed having the highest supply risk in critical minerals published by different countries. From that point of view, their extraction, and creating a secured supply chain is always crucial. In this research, the influence of calcination conditions on REE extraction from bastnasite ore was studied. Identical leaching in Ethylene Glycol (EG)-FeCl3 media which is one of the Deep Eutectic Solvents (DES) was applied to different calcines to understand calcination parameters on leaching efficiency. After conducting experiments created by Box-Behnken approach with different parameters of temperature, duration, and particles size, the highest Light Rare Earth Elements (LREE) extraction efficiency of 67.22 wt% was achieved at 900° C. However, while conducting control experiments, the highest extraction efficiency was found to be 75.986 wt% as a median of the experiments conducted at 500 °C during 180 min, and with particles finer than 25 µm. This efficiency increase with decreasing temperature is explained by Ce phase transformation from Ce2O3 to CeO2 as proved by XRD analysis. In addition to temperature, particle size was also found highly effective in extraction efficiency especially in Ce extraction. At the experiments conducted at 900 °C, and 270 min but with particles at different size ranges, Ce extraction dramatically dropped from 71.061 wt% to 9.587 wt% at the experiment conducted with finer particles. This lose in efficiency is directly correlated to increasing Ce phase transformation rate due to increasing surface area of fine particles. Non-calcined ore was also leached with DES, and only 10.977 wt% LREE could be extracted. Furthermore, it is concluded that calcination is of vital importance to transform the ore into a soluble form, and temperature, and particle size ranges are found to be two fundamental parameters for tuning the extraction efficiency.

中文翻译：

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煅烧条件对氟碳铈矿中轻稀土元素的低共熔溶剂 （DES） 浸出效率的影响


在本世纪，我们的日常生活被技术设备所包围，而稀土元素 （REE） 是这场技术革命的核心。它们总是被列为在不同国家发布的关键矿物中具有最高供应风险的。从这个角度来看，提取和创建安全的供应链始终至关重要。在这项研究中，研究了煅烧条件对氟碳铈矿中稀土提取的影响。将乙二醇 （EG）-FeCl3 介质（深度共熔溶剂 （DES） 之一）中的相同浸出应用于不同的煅烧，以了解煅烧参数对浸出效率的影响。在对温度、持续时间和颗粒大小等不同参数进行 Box-Behnken 方法创建的实验后，在 900°C 下实现了最高的稀土元素 （LREE） 提取效率，为 67.22 wt%。然而，在进行对照实验时，发现最高提取效率为 75.986 wt%，这是在 500 °C 下 180 min 和细颗粒小于 25 μm 的实验中位数。这种效率随着温度的降低而增加，可以用 Ce 从 Ce2O3 到 CeO2 的相变来解释，正如 XRD 分析所证明的那样。除温度外，粒径对提取效率也非常有效，尤其是在 Ce 提取方面。在 900 °C 和 270 min 下进行的实验中，但对于不同粒径范围的颗粒，在对更细颗粒进行的实验中，Ce 萃取率从 71.061 wt% 急剧下降到 9.587 wt%。这种效率损失与由于细颗粒表面积增加而增加的 Ce 相转变速率直接相关。未煅烧矿石也用 DES 浸出，只有 10 个。可提取 977 wt% LREE。此外，得出的结论是，煅烧对于将矿石转化为可溶形式至关重要，温度和粒度范围是调节提取效率的两个基本参数。