As a solid waste produced by coal mining, the comprehensive utilization of coal-series kaolin is the focus of attention. In this paper, the extraction of rare earth elements (REEs) from coal-series kaolin was carried out by alkali fusion and sulfamic acid leaching. The occurrence modes of REEs in coal-series kaolin was analyzed by means of inductively coupled plasma-mass spectrometry analyse and sequential chemical extraction. The influence of alkali fusion conditions on the leaching of REEs was investigated, and the activation mechanism of alkali fusion was revealed by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and field emission scanning electron microscope (FESEM) analysis. In addition, the effect of key operating parameters on the leaching efficiency of REEs from coal-series kaolin was further investigated. The results show that REEs mainly existed in silicate & aluminosilicate state of coal-series kaolin. The mineral structure was destroyed by alkali fusion, and the leaching efficiency of REEs was increased by 59.08 %. At the sulfamic acid concentration of 0.5 mol/L, H2O2 concentration of 0.2 mol/L, solid to liquid ratio of 1/50, the leaching efficiencies of total rare earth elements, light rare earth elements and heavy rare earth elements were 84.91 %, 88.43 % and 71.03 %, respectively.

中文翻译：

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通过碱熔和氨基磺酸浸出相结合，从煤系高岭土中高效提取稀土元素


作为煤炭开采产生的固体废弃物，煤系高岭土的综合利用是人们关注的焦点。本文通过碱熔和氨基磺酸浸出法从煤系高岭土中提取稀土元素 （REE）。通过电感耦合等离子体质谱分析和顺序化学萃取分析了煤系高岭土中稀土元素的赋存模式。研究了碱熔条件对稀土元素浸出的影响，并通过 X 射线衍射 （XRD）、傅里叶变换红外 （FT-IR） 和场发射扫描电子显微镜 （FESEM） 分析揭示了碱熔的活化机制。此外，进一步研究了关键操作参数对煤系高岭土稀土浸出效率的影响。结果表明，稀土元素主要存在于煤系列高岭土的硅酸盐和铝硅酸盐状态。碱熔破坏了矿物结构，稀土元素的浸出效率提高了 59.08 %。在氨基磺酸浓度为 0.5 mol/L、H2O2 浓度为 0.2 mol/L、料液比为 1/50 时，总稀土元素、轻稀土元素和重稀土元素的浸出效率分别为 84.91 %、88.43 % 和 71.03 %。