One of the potential sources of rare-earth elements (REE) is the industrial waste known as red mud (bauxite residue), in which the majority of REE from the initial bauxite are concentrated via the Bayer process. Therefore, the studies of the subject, both in Russia and outside, focus almost exclusively on red mud processing. This article looks into the possibility of REE concentration into red mud by leaching an intermediate product of the bauxite sintering process at Russian alumina refineries, namely electrostatic precipitator (ESP) dust. The experimental works were performed by X-ray diffraction (XRD)and electron probe microanalysis (EPMA) of the sinter and sinter dust. The determination of major and rare-earth elements in the sinter from the rotary kilns and in the ESP dust before and after leaching was carried out by X-ray fluorescence (XRF) and plasma mass spectrometry (ICP-MS). The study showed that it is possible to obtain red mud that contains three times more REE than traditional waste red mud after two-stage leaching ESP dust in the water at 95 °C followed by leaching in an alkaline-aluminate liquor at 240 °C. The shrinking core model was used to study the kinetics of leaching of the original ESP dust and water-treated dust in alkaline-aluminate liquor. The study showed the change in the limiting stage of the alkaline leaching process after water treatment, with the activation energy growing from 24.98 to 33.19 kJ/mol.

中文翻译：

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水和铝土矿烧结粉碱浸出获得的铝土矿残渣（红色泥浆）中的稀土元素（Sc，Y，La，Ce，Nd，Sm）浓度

稀土元素（REE）的潜在来源之一是被称为赤泥（铝土矿残渣）的工业废物，其中最初的铝土矿中的大部分REE通过拜耳法进行浓缩。因此，无论是在俄罗斯还是在国外，对该主题的研究几乎都集中在赤泥加工上。本文研究了通过在俄罗斯氧化铝精炼厂浸出铝土矿烧结过程的中间产品（即静电除尘器（ESP）粉尘）将REE浓缩到赤泥中的可能性。通过对烧结矿和烧结尘的X射线衍射（XRD）和电子探针显微分析（EPMA）进行实验。通过X射线荧光（XRF）和等离子体质谱（ICP-MS）进行了回转窑烧结矿中和电除尘器中粉尘中主要和稀土元素的测定。研究表明，在95°C的水中分两步过滤ESP尘土，然后在240°C的碱铝酸盐溶液中进行淋滤后，可以获得比传统的废赤泥多三倍的REE的赤泥。收缩核模型用于研究碱性铝酸盐溶液中原始ESP粉尘和水处理粉尘的浸出动力学。研究表明，水处理后碱浸过程的极限阶段发生了变化，活化能从24.98 kJ / mol增加到33.19 kJ / mol。研究表明，在95°C的水中分两步过滤ESP尘土，然后在240°C的碱铝酸盐溶液中进行淋滤后，可以获得比传统的废赤泥多三倍的REE的赤泥。收缩核模型用于研究碱性铝酸盐溶液中原始ESP粉尘和水处理粉尘的浸出动力学。研究表明，水处理后碱浸过程的极限阶段发生了变化，活化能从24.98 kJ / mol增加到33.19 kJ / mol。研究表明，在95°C的水中分两步过滤ESP尘土，然后在240°C的碱铝酸盐溶液中进行淋滤后，可以获得比传统的废赤泥多三倍的REE的赤泥。收缩核模型用于研究碱性铝酸盐溶液中原始ESP尘土和水处理尘土的浸出动力学。研究表明，水处理后碱浸过程的极限阶段发生了变化，活化能从24.98 kJ / mol增加到33.19 kJ / mol。收缩核模型用于研究碱性铝酸盐溶液中原始ESP粉尘和水处理粉尘的浸出动力学。研究表明，水处理后碱浸过程的极限阶段发生了变化，活化能从24.98 kJ / mol增加到33.19 kJ / mol。收缩核模型用于研究碱性铝酸盐溶液中原始ESP粉尘和水处理粉尘的浸出动力学。研究表明，水处理后碱浸过程的极限阶段发生了变化，活化能从24.98 kJ / mol增加到33.19 kJ / mol。