CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Tingliang Xie,Minxuan Chen,Cong Xu,Jing Chen
Microextractors are known to provide high mass transfer rates for the extraction and separation of rare-earth elements (REEs). High-throughput microextractors are essential for industrial-scale production of REEs, but few practical studies have been conducted to date. In this work, a chaotic advection microextractor, i.e., a three-stage microextractor, was designed and demonstrated to extract Pr(III) and Ce(III) efficiently from nitric acid media at high throughputs by using 2-ethylhexyl phosphoric acid-2-ethylhexyl ester (P507) and sulfonated kerosene as an extraction agent and a diluent, respectively. Flow visualization experiments showed that the dispersed phase could be effectively broken into small droplets owing to vortex and recirculation flows. Microextraction experiments performed under optimal extraction conditions indicated that at low throughputs, the concentration ratio D , extraction efficiency E , and separation factor β decreased with an increase in the throughput, whereas at high throughputs, D , E , and β increased with an increase in the throughput. An extraction efficiency close to that of co-current balanced extraction was successfully achieved, even at a high total throughput of 100 mL/min and a rather short residence time of 0.029 s. Thus, the chaotic advection microextractor features a high throughput and high extraction efficiency, which are appropriate for the high-efficiency extraction and separation of REEs.
研究领域:
化学工程
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分离科学
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稀土冶金
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微流控技术
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过程强化
✓ 已验证
DOI
高影响因子
JOURNAL OF RARE EARTHS
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2017
·Vol. 36
·期 3
·304-310
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IF 2.429
Shengting Kuang,Zhifeng Zhang,Yanling Li,Haiqin Wei,Wuping Liao
The extraction and separation of heavy rare earths (REs) using newly synthesized α-aminophosphonic acid extractant 2-ethylhexyl-3-(2-ethylhexylamino)pentan-3-yl phosphonic acid (HEHAPP, H A ) in n-heptane were investigated from chloride medium. The extraction stoichiometries of lanthanum , gadolinium , yttrium and lutetium are determined to be RE A 3 by the slope analysis method. The favorable separation factors of adjacent heavy REs(Ⅲ), i.e. β Y/Ho , β Er/Y , β Tm/Er , β Yb/Tm and β Lu/Yb , are determined to be 1.87, 1.36, 3.21, 3.22 and 1.93, respectively, when extracted from a binary system at proper condition. The loading capacities of H A for Ho, Er, Yb and Lu increase in the order Ho < Er < Yb < Lu with the values being 0.201, 0.205, 0.216 and 0.229 mol/L, respectively. So H A would be a potential extractant for the separation of heavy REs(Ⅲ). Among inorganic acids such as H 2 SO 4 , HNO 3 and HCl, HCl is tested to be the most effective stripping agent.
研究领域:
湿法冶金
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稀土化学
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分离科学与技术
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无机化学
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萃取化学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2018
·
IF 3.141
Pan Sun,Kun Huang,Weiyuan Song,Zhen Gao,Huizhou Liu
An ionic-liquid-based aqueous two-phase system (iL-ATPS) consisting of an ionic liquid, tributylmethylammonium nitrate (N4441NO3), and NaNO3 aqueous solutions was developed for the extraction and separation of rare-earth ions, for example Nd(III), from transition-metal ions. The excellent selectivity of a green nonfluorinated ionic liquid and the low-viscosity feature of an aqueous two-phase system were combined in our suggested iL-ATPS. The results indicated that efficient separation of Nd(III) from transition-metal ions, Fe(III), Ni(II), and Co(II), could be obtained in our suggested iL-ATPS. Furthermore, different parameters of the separation process, including the concentrations of HNO3 and NaNO3 and the added amount of N4441NO3, were optimized. Notably, the extraction kinetics of Nd(III) could be improved significantly in the present iL-ATPS compared with the conventional organic-solvent-based ionic-liquid extraction systems. The similar environment across the liquid–liquid interface was revealed by the ultralow viscosity and interfacial tension of the ionic-liquid-rich phase in the iL-ATPS. This feature was responsible for the enhanced extraction kinetics of Nd(III). In addition, the structures of the extraction complexes were elucidated by using NMR spectroscopy and molecular simulations. It was demonstrated that NO3– ions were in the inner coordination shell of Nd(III) ions to interact with Nd(III) ions, while N4441+ surrounded Nd(III) ions at the outer coordination shell of Nd(III) ions. Moreover, 2 mol/L HNO3 aqueous solutions could be used to effectively strip Nd(III) from the loaded ionic-liquid-rich phase. After 5 cycles, the extraction performance of the ionic liquid remained nearly unchanged. The present work highlights an environmental method to selectively separate rare-earth ions from the complicated solutions coexisting with other transition-metal impurity ions. It provides a basis for the future application in recycling of rare-earth elements from the spent NdFeB magnets.
研究领域:
环境化学
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湿法冶金
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可持续回收
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分离科学
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稀土元素
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）