Selective separation of yttrium and europium using Cyanex 572 for applications in fluorescent lamp waste processing
Selective separation of yttrium and europium using Cyanex 572 for applications in fluorescent lamp waste processing
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DOI：
10.1016/j.hydromet.2016.10.012
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发表时间：
2016-12-01
期刊：
影响因子：
4.7
通讯作者：
Retegan, Teodora
中科院分区：
文献类型：
--
作者：
Tunsu, Cristian;Lapp, Jean Baptiste;Retegan, Teodora
对循环经济的追求将注意力转向了对报废产品和工业流的处理，以回收其中包含的有价值的部分。荧光灯废物被认为是钇和铕的重要来源，这两种稀土元素目前被认为具有关键的供应风险。在这项研究中，一个商业萃取剂的溶剂萃取分离的稀土，Cyanex 572，成功地应用于分离钇和铕的荧光灯废水处理过程中获得的解决方案。在pH（eq）= 0时，钇与铕选择性分离，然后在pH（eq）= 1时进一步回收铕。与芳香族稀释剂或长链醇相比，使用脂肪族稀释剂如煤油实现了更好的稀土萃取效率。在25-65摄氏度范围内的温度升高导致钇和铕之间的分离因子降低。用浓度高于3 M的盐酸溶液进行汽提，可完全回收萃取的钇和铕。用草酸将这些元素从它们各自的反萃取产物中沉淀出来，然后煅烧沉淀物，得到纯度分别为99.82%和91.60%的氧化钇和氧化铕。还介绍了一个流程图，包括荧光灯废物处理的主要步骤。(C)2016爱思唯尔B. V.保留所有权利。
The quest for a circular economy has directed attention towards processing of end-of-life products and industrial streams to recover the valuable fractions these contain. Fluorescent lamp waste is acknowledged to be an important source of yttrium and europium, two of the rare earth elements presently regarded as having critical supply risk. In this study, a commercial extractant for solvent extraction separations of REEs, Cyanex 572, was successfully applied to separate yttrium and europium from solutions obtained during processing of fluorescent lamp waste streams. Yttrium was selectively separated from europium at pH(eq) = 0, followed by further recovery of europium at pH(eq) = 1. Better extraction efficiencies of REEs were achieved using aliphatic diluents e.g. kerosene in comparison to aromatic diluents or long chain alcohols. Increases in temperature in the range 25-65 degrees C led to decreases in the separation factors between yttrium and europium. Stripping with hydrochloric acid solutions at concentrations higher than 3 M led to complete recovery of extracted yttrium and europium. Precipitation of these elements from their respective stripping products with oxalic acid, followed by calcination of the precipitate, led to yttrium and europium oxides of 99.82% and 91.60% purity, respectively. A flowsheet that encompass the main steps for fluorescent lamp waste processing is also presented. (C) 2016 Elsevier B.V. All rights reserved.