膦(磷)类萃取剂浸渍树脂吸附重稀土的性能

利用静态法研究了5种不同膦(磷)类萃取剂的浸渍树脂在盐酸介质中对重稀土的吸附行为. 结果表明,Cyanex272与膦(磷)类萃取剂组成的双萃取剂的浸渍树脂在同等实验条件下比单一Cyanex272萃取剂的浸渍树脂对重稀土具有更好的吸附性,其中以Cyanex272与P507, Cyanex302, Cyanex923和TBP分别按体积比1:1, 5:1, 1:1, 2:1混合为最优. 吸附最佳pH值在3.0~4.0之间,吸附平衡时间为50 min,升高温度对吸附有利. 在相同实验条件下,5种浸渍干树脂Cyanex272, Cyanex272-P507, Cyanex272-Cyanex302, Cyanex272-Cyanex923, Cyanex272-TBP对重稀土的饱和吸附容量分别为20.04, 25.37, 21.87, 22.16, 38.48 mg/g.     

Cyanex272浸渍树脂支持体的选择及性能表征

以非极性HPD100,HPD300,中极性HPD400,HPD450和极性HPD500,HPD800三类大孔吸附树脂为Cyanex272浸渍树脂支持体进行研究和比较.结果表明,大孔树脂对Cyanex272的浸渍率与树脂的比表面积和平均孔径有关.HPD800大孔吸附树脂是Cyanex272浸渍树脂分离重稀土良好的支持体,对萃取剂的浸渍率为40.22%,吸附重稀土的量为9.94 mg/g,经过9次循环后的损失率为1.88%,且在水及盐酸溶液中稳定性良好.     

酸性有机磷萃取剂对镓的萃取研究

水相初始pH值=2. 0时,0. 3 mol/L的酸性有机磷萃取剂基本可以实现对盐酸溶液中镓的完全萃取,且萃取能力遵循萃取剂的酸度顺序:D2EHPA(99. 2%) PC88A(98. 3%) Cyanex 272(76. 9%)。随着水相初始pH值升高,越来越多的镓被萃取到有机相,且由于氢离子的释放导致较高的平衡pH值。通过FT-IR分析了D2EHPA的P=O及P-O的吸收峰明显大于PC88A、Cyanex 272。另外,3mol/L的盐酸溶液作为反萃剂对D2EHPA、PC88A、Cyanex 272的负载有机相进行反萃时,镓的反萃率达到最高,分别为81. 7%、85. 5%、93. 5%。最后,利用斜率分析法推导出三种酸性含磷萃取剂的萃取机理方程式:Ga(OH)_(2,org)~++(HA)_(2,org)=Ga(OH)_2A·(HA)_(org)+H_(aq)~+。     

萃取色层技术分离提纯稀土的现状与展望

萃取技术分离难以分离得到高纯单一重稀土,尚需萃取色层技术.本综述简要介绍了萃取色层分离技术要点,对国内外萃取色层技术分离提纯稀土的现状和发展情况进行了综述和分析,提出了萃取色层技术分离提纯稀土所面对的关键技术问题和展望.迄今用于稀土元素分离的萃淋树脂所含的萃取剂主要为酸性含磷萃取剂,包括P507,P204,5709等,制约其工业化应用的主要原因是淋洗酸浓度过高、且需采用梯度淋洗.Cyanex272萃淋树脂是分离稀土的发展方向.结论指出,应加强萃淋树脂对金属萃取饱和容量的提高、减少萃取剂损失及加强传质数学模型等基础课题的研究,为工业应用提供理论依据.预计萃淋树脂技术将会在稀土元素的分离中得到实际广泛的应用.     

P507与Cyanex272协同萃取分离溶液中钴镍离子

采用P507与Cyanex272协同萃取分离回收浸出液中的Ni2+, Co2+,考察了初始pH值、有机相复配比(P/C)和水油相比(A/O)的影响. 结果表明,协萃优化条件为：有机相皂化率50%,皂化时间30 min;有机相组成为10%复配萃取剂[P507:Cyanex272为3:2(j)]+85%磺化煤油+5% TBP;相比为3:1,水相pH值为2.5. 在此条件下,Co2+的一级萃取率为92.96%. 利用200 g/L硫酸反萃负载有机相,在相比2:3、振荡强度225 r/min、时间4 min的条件下,Co2+的反萃率为98.68%,实现了低pH值下Ni2+和Co2+的萃取分离.     

萘磺酸类染料废水络合萃取机理研究

研究络合萃取体系处理萘磺酸类染料废水的作用及萃取机理,选取苯磺酸和叔胺(二甲苯)萃取剂组成的体系对萃合物的化学组成、萃取反应平衡常数K、萃取过程热效应进行了研究。结果表明,胺盐萃合物结构式为[0.63R3N·HA],K=17.51L/mol,萃取过程为放热反应。     

HA和HNAPO萃取锌的密度泛函分析

为从微观层面分析从锌氨溶液中萃取Zn(II)的反应机理,采用密度泛函(DFT) B3LYP/6-31G+(d, p)理论对萃取剂1-苯基-1,3癸二酮(Mextral54-100,HA)和2-羟基-5-壬酰基苯甲酮肟(Lix84I,HNAPO)及Zn(II)萃合物的几何结构、红外光谱、原子轨道贡献率和电荷分布等进行研究。结果表明,在HA与锌形成萃合物的过程中,HA烯醇式上的O和C原子、HNAPO肟基上的C和N原子及苯酚上的O原子对分子轨道的贡献率最高;HA上的C=C双键的伸缩振动峰在萃取反应后发生红移,HNAPO肟基上的C=N双键的伸缩振动峰强度发生改变,酚羟基的摇摆振动峰消失,表明烯醇式、肟基和酚羟基为萃取反应的活性中心,键长和键角均发生了改变;Zn(II)取代烯醇式上的氢与氧原子形成配位键,C=O双键在形成萃合物后键长增大。HNAPO与锌形成萃合物的过程中,Zn(II)取代酚羟基上的氢与氧和氮原子形成配位键,且苯环和锌离子处于一个平面上;萃取剂HA的分子轨道差值和电负性均低于HNAPO,化学势高于HNAPO,理论预测HA萃取锌的反应活性大于HNAPO,与实验结果吻合。     

Metral54-100萃取分离铜、镍的密度泛函研究

采用密度泛函理论DFT/B3LYP/6-31G+(d, p)方法计算不同配位形态的铜、镍萃合物的结合能、全局活性指数、局部活性指数和红外光谱,探讨了1-苯基-1,3癸二酮(Mextral54-100)萃取Cu(II), Ni(II)的行为及机理。结果表明,Mextral54-100对Cu(II)的萃取能力大于Ni(II)。在反萃过程中,铜的萃合物更易被反萃。萃合物羰基表现出最高的反应活性,为活性中心。萃合物中氨分子的取代数越多,萃合物构型近似于稳定的八面体结构。配体氨逐一被萃取剂的羰基取代,有效避免共萃氨。Mextral54-100从铜、镍氨混合溶液中萃取–反萃Cu(II)和Ni(II)的实验结果与理论预测结果吻合,进一步通过FT-IR证实了理论计算结果的准确性,密度泛函理论有望成为一种研究萃取分离性能的新方法。     

硝酸体系中Cyanex923萃取和反萃镱的性能研究

研究了中性萃取剂三烷基氧膦混合物Cyanex923对稀土元素Yb(Ⅲ)的萃取和反萃性能.考察了振荡时间、金属离子浓度、Cyanex923浓度、硝酸根浓度对Yb(Ⅲ)萃取的影响,由斜率分析法确定了反应机理,获得了萃取平衡方程.并探讨了温度对Cyanex923萃取Yb(Ⅲ)的影响,由van't Hoff方程计算出298～3...     

三烷基氧膦与二(2-乙基己基)磷酸协萃对氨基苯酚的研究和应用

为考察复合萃取剂萃取两性官能团溶质的协萃机理,以对氨基苯酚(PAP)为分离溶质,三烷基氧膦(TRPO)+二(2 乙基己基)磷酸(D2EHPA)+庚烷为萃取剂进行了萃取平衡特性的研究。结果表明,该萃取剂萃取PAP时,具有明显的协萃效应。协萃机理为TRPO与PAP的中性分子以及D2EPHPA与PAP的中性分子和阳离子反应生成(HP)2·NH2—C6H4—OH·TRPO或者P·NH3—C6H4—OH·TRPO萃合物;萃取剂中D2EHPA与TRPO的适宜协萃比为1∶3;pH是影响萃取能力的关键因素,起始pH值条件下PAP分子形态摩尔分数较大的pH值区域(6—8),分配系数出现极大值;采用适宜的萃取剂组成对PAP的工业生产废水进行处理,可有效去除废水中的PAP和苯胺。     

Synergistic Effect of D2EHPA and Cyanex 272 on Separation of Zinc and Manganese by Solvent Extraction

The effect of bis-2-ethylhexylphosphoric acid (D2EHPA), bis (2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272), and tri-butyl phosphate (TBP) and their mixtures in various proportions for the separation and extraction of zinc and manganese from sulfate solutions were investigated. Experiments were carried out in the pH range of 0.5–5.0 at 25, 40, and 60°C. It was shown that the extraction of zinc and manganese by D2EHPA and/or Cyanex 272 can be increased by the increase in pH and temperature. The synergistic extraction and separation of zinc and manganese with a mixture of D2EHPA and Cyanex 272 was studied and the results showed that mixing the two extractants improved the extraction capacity of the mixture. Increasing the D2EHPA to Cyanex 272 ratio in the organic phase, caused a right shifting of extraction isotherms of manganese and zinc; shifting the manganese curve was more than zinc. The manganese curve had considerable right shifting with 5% D2EHPA and 15% Cyanex 272. TBP did not affect the zinc (Zn) and manganese (Mn) extraction. The stoichiometric coefficients of Zn and Mn were determined with 20% and 5% D2EHPA and 15% Cyanex 272 by applying the slope analysis method. The organic phase was stripped by sulfuric acid.     

SYNERGISTIC EXTRACTION OF ZINC(II) BY MIXTURES OF PRIMARY AMINE N1923 AND CYANEX272

ABSTRACT

The extraction of zinc(II) and cadmium(II) from chloride solution by mixtures of primary amine N1923 and Cyanex272 (HA) was studied. The synergistic effect was observed for the extraction of zinc(II) while no synergistic effect for cadmium(II), which makes it possible to separate zinc(II) and cadmium(II) with the mixtures. The results showed that zinc(II) was extracted as (RNH₃Cl)₃·ZnClA instead of ZnA₂·2HA which was extracted by Cyanex272 alone. The extraction mechanism was discussed and the formation constants and thermodynamic functions were determined. The separation factors between zinc(II) and cadmium(II) were calculated.     

Synergistic Extraction and Separation of Heavy Lanthanide by Mixtures of Bis(2,4,4‐trimethylpentyl)phosphinic Acid and 2‐Ethylhexyl Phosphinic Acid Mono‐2‐Ethylhexyl Ester

Abstract

The extraction of Yb³⁺ from chloride solution has been studied using mixtures of bis(2,4,4‐trimethylpentyl)phosphinic acid (Cyanex272) and 2‐ethylhexyl phosphinic acid mono‐2‐ethylhexl ester (P507). The results show that Yb³⁺ is extracted into heptane as YbA₃(HA)₃ with Cyanex272, YbL₃(HL)₃ with P507, and YbA₂L₄H₃ with synergistic mixture. The equilibrium constants, formation constants, and thermodynamic functions have been determined. Extraction mechanism and extraction process are also proposed. The extraction of heavy lanthanide ions by mixtures of Cyanex272 and P507 is studied and the possibility of separating heavy rare earth ions is discussed.     

Kinetics and Mechanism of Yb(III) Extraction and Separation from Y(III) with Mixtures of bis(2,4,4‐trimethylpentyl)phosphinic acid and2‐ethylhexyl phosphonic acid mono‐2‐ethylhexyl ester

Abstract

The ytterbium(III) extraction kinetics and mechanism with mixtures of bis(2,4,4‐trimethylpentyl)phosphinic acid (Cyanex272) and 2‐ethylhexyl phosphonic acid mono‐2‐ethylhexyl ester (P507) dissolved in heptane have been investigated by constant interfacial cell with laminar flow. The effects of the stirring rate, temperature, extractant concentration, and pH on the extraction with mixtures of Cyanex272 and P507 have been studied. The results are compared with those of the system with Cyanex272 or P507 alone. It is concluded that the Yb(III) extraction rate is enhanced with mixtures extractant of Cyanex272 and P507 according to their values of the extraction rate constant, which is due to decreasing the activation energy of the mixtures. Atthe same time, the mixtures exhibits no synergistic effects for Y(III), which provides better possibilities for Yb(III) and Y(III) separations at a proper conditions than anyone alone. Moreover, thermodynamic extraction separation Yb(III) and Y(III) by the mixtures has been discussed, which agrees with kinetics results. Extraction rate equations have also been obtained, and through the approximate solutions of the flux equation, diffusion parameters and thickness of the diffusion film have been calculated.     

Separation of cobalt and zinc from concentrated nickel sulfate solutions with Cyanex 272

BACKGROUND: Removal of cobalt and zinc from concentrated nickel solutions separately using two Cyanex 272 circuits has been practised in the nickel industry. However, no detailed study has been conducted and data are scarce for further improvement. This study aims to optimise the operating conditions and to simplify the process flowsheet. RESULTS: With a synthetic solution containing 100 g L^?1 Ni, 1.4 g L^?1 Co and 0.8 g L^?1 Zn and the organic solution containing Cyanex 272 and TBP in Shellsol D70, the operating conditions of extraction, scrubbing and stripping were optimised. McCabe–Thiele diagrams were constructed to determine the theoretical extraction and stripping stages and a flowsheet to separate cobalt and zinc from nickel was proposed. With this flowsheet, more than 99% cobalt and zinc could be separated, resulting in a pure nickel solution with less than 10 mg L^?1 of cobalt and zinc. CONCLUSIONS: The current study shows that Cyanex 272 can be used to separate cobalt and zinc in one Cyanex 272 circuit effectively from concentrated nickel solutions to obtain very pure nickel solutions suitable for nickel electrowinning or hydrogen reduction. The cobalt and zinc in the loaded strip liquor were concentrated over 10 times and can be separated readily in another much smaller solvent extraction circuit. Copyright © 2010 Society of Chemical Industry     

Solvent Extraction and Separation of Trivalent Lanthanides Using Cyphos IL 104, a Novel Phosphonium Ionic Liquid as Extractant

Solvent extraction of trivalent lanthanides from chloride solution using a novel ionic liquid Cyphos IL 104 (trihexyl(tetradecyl)phosphonium bis-2,4,4-(trimethylpentyl) phosphinate or [R₄PA]) has been investigated, while comparing the results with that of its precursors trihexyl(tetradecyl)phosphonium chloride [R₄PCl or Cyphos IL 101], Cyanex 272 [HA] and their equimolar mixture. The results also indicate very high extractability of Cyphos IL 104 toward trivalent lanthanides. Unlike the conventional acidic extractants, extraction of trivalent lanthanides with Cyphos IL 104 increases the equilibrium pH of the aqueous phase due to the preferential extraction of acid over the lanthanide ions. Extraction mechanism has been established by studying the extraction of neodymium(III) with the ionic liquid as a function of the concentrations of Cyphos IL 104 and chloride ions. Separation studies of trivalent lanthanides from a mixed solution containing 1 × 10^?4M each of La, Nd, Gd, and Lu with Cyphos IL 104 or Cyanex 272 indicate that Cyphos IL 104 is a better extractant in terms of extraction coefficient, but Cyanex 272 exhibits better selectivity toward heavier lanthanides. The prospects of stripping and regeneration of ionic liquid (Cyphos IL 104) have also been discussed in the present study.     

Kinetics,Equilibrium, and Thermodynamic of Pb(II) Biosorption by Citric Acid Modified Lawny Grass Containing Cyanex272

Lawny grass loaded Cyanex272 prepared by solid-liquid grind was used to remove Pb(II) in the batch and column process. Carboxylic groups were introduced to the grass by citric acid modification and Cyanex272 was successfully immobilized on grass. The removal rate of Pb(II) on 272-1CG is close to 100%. Cyanex272 also played an important role in improving maximum adsorption capacities from 328 to 380 mg/g and shortening equilibrium time from 60 min to 40 min. Thermodynamic results indicate the adsorption of Pb(II) is spontaneous and endothermic. 0.1 mol/L HCl is used as eluent and desorption percentages reach 95.1%.     

Interfacial Behavior of Cyanex 272 and Mass Transfer Kinetics of Ytterbium Using the Constant Interfacial Area Cell

The interfacial behavior of Cyanex 272 has been investigated using the Du Nouy ring method. Different adsorption isotherms such as the Gibbs and Szyszkowski isotherms have been found as fitting well to the experimental data. The values of interfacial excess at the saturated interface increase in the following order: n-heptane > cyclohexane > CCl₄ > toluene > benzene > chloroform, explained according to the stronger solution effect of aromatic hydrocarbon. The effects of temperature, acidity, and ionic strength of the aqueous phase on the interfacial activity of Cyanex 272 are also examined and explained in detail. Moreover, the reaction orders against Cyanex 272 predicted from the interfacial tension isotherms are in agreement with the order determined experimentally, which suggests that the interfacial activity of Cyanex 272 can provide enough strong evidence quantitatively supporting the interfacial mechanism.     

Separation and recovery of heavy metals from concentrated smelting wastewater by synergistic solvent extraction using a mixture of 2-hydroxy-5-nonylacetophenone oxime and bis(2,4,4-trimethylpentyl) -phosphinic acid

Extraction and separation of copper, zinc, nickel, and cadmium from calcium and magnesium in concentrated smelting wastewater by synergistic solvent extraction using a mixture of 2-hydroxy-5-nonylacetophenone oxime (Mextral 84H) and bis(2,4,4 -trimethylpentyl)-phosphinic acid (Cyanex 272) in an aliphatic diluent (DT-100) was studied. The effects of extractant concentrations, equilibrium pH, organic-to-aqueous phase ratios, system temperature, and extraction and stripping efficiencies on the extraction performance of the heavy metals were investigated. Extraction of pH isotherms showed that addition of Cyanex 272 to Mextral 84H causes obvious synergistic shifts for zinc and cadmium and a slightly antagonistic shift for nickel. The separation factor of cadmium over magnesium was 155.7 and the ΔpH₅₀ values between the metals were over 1.00 pH units. Semi-continuous tests for the metals extraction, scrubbing, and stripping were conducted in a continuous extraction apparatus with conditions further optimized for separation of the metals. Nearly 100% of the copper and nickel and over 98% of the zinc and cadmium were recovered with less than 0.1 mg/L copper and nickel, 26 mg/L of zinc, and 10 mg/L of cadmium remaining in the raffinate. A process in which all valuable metals are extracted simultaneously and stripped selectively at optimal conditions is proposed that is entirely feasible for the separation of copper, zinc, nickel, and cadmium from calcium and magnesium in concentrated smelting wastewater. The study determines the fundamental parameters for the treatment of smelting wastewater by solvent extraction.     

Kinetics of Y(III) Stripping for the System Y/HCl/Cyanex 272‐P507/Heptane with Constant Interfacial Area Cell with Laminar Flow

Abstract

Kinetics and mechanism of stripping of yttrium(III) previously extracted by mixtures of bis(2,4,4‐trimethylpentyl)phosphinic acid (Cyanex 272, HA), and 2‐ethylhexyl phosphonic acid mono‐2‐ethylhexl ester (P507, HB) dissolved in heptane have been investigated by constant interfacial‐area cell by laminar flow. The corresponding equilibrium stripping equation and equilibrium constant were obtained. The studies of effects of the stirring rate and temperature on the stripping rate show that the stripping regime is dependent on the stripping conditions. The plot of interfacial area on the rate has shown a linear relationship. This fact together with the strong surface activity of mixtures of Cyanex 272 and P507 at heptane‐water interfaces makes the interface the most probable locale for the chemical reactions. The stripping rate constant is obtained, and the value is compared with that of the system with Cyanex 272 and P507 alone. It is concluded that the stripping ability with the mixtures is easier than that of P507 due to lower the activation energy of the mixtures. The stripping rate equation has also been obtained, and the rate‐determining steps are the two‐step interfacial chemical reactions as predicted from interfacial reaction models.