Selective Recovery of Platinum (IV) from HCl Solutions Using 2-Ethylhexylamine as a Precipitant
Selective Recovery of Platinum (IV) from HCl Solutions Using 2-Ethylhexylamine as a Precipitant
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DOI：
10.3390/separations8040040
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发表时间：
2021-04
期刊：
影响因子：
2.6
通讯作者：
Kazuya Matsumoto;Yuto Sezaki;Yukinori Hata;M. Jikei
中科院分区：
文献类型：
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作者：
Kazuya Matsumoto;Yuto Sezaki;Yukinori Hata;M. Jikei
从金属混合物中选择性分离和回收特定的铂族金属（PGMs）是一个重大挑战，因为这些金属在化学和物理性质方面相似。在典型的铂族金属（Pd、Pt和Rh）中，在回收Pd和Rh之前选择性回收Pt的要求很高。在这项研究中，我们尝试了选择性沉淀Pt（IV）从混合金属盐酸溶液中使用2-乙基己胺（2 EHA）作为沉淀剂，并实现了选择性沉淀Pt（IV）从Pd（II）和Rh（III）在很宽的HCl浓度范围。Pt（IV）的选择性沉淀也从具有高水平的贱金属（例如Al、Cu、Fe和Zn）的HCl溶液中实现。使用疏水性多孔树脂回收Pt（IV）沉淀后HCl溶液中剩余的未降解2 EHA的高产率。X射线光电子能谱和热重测量表明，含Pt（IV）的沉淀物是由一个[PtCl 6]2−和两个2 EHA铵阳离子组成的离子对。2 EHA的空间位阻和高亲水性分别抑制了含Rh（III）和Pd（II）沉淀的形成，导致Pt（IV）的选择性沉淀。
The selective separation and recovery of specific platinum-group metals (PGMs) from metal mixtures is a significant challenge owing to the similarity of these metals in terms of chemical and physical properties. Among the typical PGMs (Pd, Pt, and Rh), the selective recovery of Pt prior to the recovery of Pd and Rh is in high demand. In this study, we attempted the selective precipitation of Pt(IV) from mixed-metal HCl solutions using 2-ethylhexylamine (2EHA) as a precipitant and achieved the selective precipitation of Pt(IV) from Pd(II) and Rh(III) over a wide range of HCl concentrations. Selective precipitation of Pt(IV) was also achieved from HCl solutions with high levels of base metals, such as Al, Cu, Fe, and Zn. High yields of undegraded 2EHA remaining in the HCl solution after Pt(IV) precipitation were recovered using hydrophobic porous resins. X-ray photoelectron spectroscopy and thermogravimetric measurements revealed that the Pt(IV)-containing precipitate was an ion-pair comprising one [PtCl6]2− and two ammonium cations of 2EHA. The steric hindrance and high hydrophilicity of 2EHA suppressed the formation of Rh(III)- and Pd(II)-containing precipitates, respectively, resulting in the selective precipitation of Pt(IV).