膜基萃取过程中在线分析技术及其在钕钐传质中的应用

采用氢离子电极和氨气敏电极与流动注射分析相结合的在线分析技术,对中空纤维膜器中氨化HEH/EHP-煤油体系萃取钕、钐过程的氢离子及铵离子进行在线分析.结果表明,通过对电极流动池的改进及工作条件的选择,氢离子电极和氨气敏电极均可较好地实现离子的在线分析功能.通过对氨化HEH/EHP萃取钕、钐的研究,提出了氨化HEH/EHP在膜基萃取过程中,H+和NH4+的传质规律.同级萃取反萃取过程中,也有相同的结论.     

HDEHP萃取Ni（Ⅱ）的研究

考察了ＨＤＥＨＰ在氯仿和四氯化碳两种稀释剂中萃取Ｎｉ（Ⅱ）的热力学和动力学，确定其在不同稀释剂中的萃取平衡和反应机理及反应速率方程，并讨论了稀释剂对萃取的影响。     

HDEHP萃取稀土过程的溶剂效应

考察了在不同溶剂中ＨＤＥＨＰ对镨、钕、钐、镝、钬、镱等的萃取，计算得到萃取表观平衡常数Ｋｅｘ、热力学平衡常数ＫΘｅｘ和萃合物的溶解度参数δｃ，建立了ｌｇＫｅｘ与溶剂极性参数ＥＴ（３０）、α间的经验方程。发现溶剂性质不会影响萃取机理，但使ＨＤＥＨＰ二聚体间的作用程度不同，而且显著影响萃取平衡关系。稀土离子萃合物的溶解度参数δｃ基本相同，萃合物的空间构型相同。     

在HClO4介质中P538萃取钯机理的研究

本文介绍了用Ｐ５３Ｂ从高氯酸体系中萃取钯机理研究。结果表明，钯的萃取率随ｐＨ的增大而增大，而与高氯酸根离子浓度、钯离子浓度无关。采用斜率法测得萃合物组成为：Ｐｄ·２ＨＰ５３８。萃取反应方程式为：２Ｈ２Ｐ５３８（ｏ）＋Ｐｄ＝Ｐｄ·２ＨＰ５３３（Ｏ）＋２Ｈ     

HDEHP萃取Ga(Ⅲ)机理的研究

ＨＤＥＨＰ萃取Ｇａ（Ⅲ）机理的研究刘桂华李小斌孙思修（中南工业大学冶金系，长沙４１００８３）（山东大学化学院）关键词：Ｇａ（Ⅲ）萃取机理ＨＤＥＨＰ镓是重要的稀有金属，在自然界中，镓伴生于其他矿物中，通过溶剂萃取来分离、富集镓的化合物是镓冶炼中一种重要...     

双水相萃取体系传输Cu（Ⅱ）,Zn（Ⅱ）

考察了双水相萃取体系中源相酸度、萃取剂ＨＥＨ［ＥＨＰ］浓度对Ｃｕ（Ⅱ）、Ｚｎ（Ⅱ）传输的影响；研究了其萃取动力学过程；推断了该过程的反应机理。并对应用该体系分离Ｃｕ（Ⅱ）、Ｚｎ（Ⅱ）进行了简要讨论。     

液膜法分离富集测定水中痕量镉

用ＨＥＨＥＨＰ、ＴＯＰＯ、ＳＰＡＮ８０、液体石蜡、煤油和内相乳状液膜体系，研究了Ｃｄ＾２＋的迁移行为，只有Ｃｄ＾２＋能与各种阳离子得到满意的分离。最佳液膜体系的体积比为４％ＨＥＨＥＨＰ、３％ＴＯＰＯ、５％ＳＰＡＮ８０、４％液体石蜡、８４％煤油，内相为３ｍｏｌ／Ｌ ＨＣｌ溶液。同时还确定了分离富集Ｃｄ＾２＋的最优实验条件，经法用于水和工业废水中痕量镉，其加嘏率为９９．４％以上，相对标准偏差在３．８％     

Cyanex272与HEHEHP混合体系萃取分离重稀土的研究

选定了ＨＥＨＥＨＰ与Ｃｙａｎｅｘ ２７２组成混合体系,确定了萃取体系的最佳组成,测定了该体系的萃取容量、反萃酸度以主相邻重稀土元素之间的分离系数,考察了体系萃取性能的主要影响因素。     

PC-88A为载体的液膜体系传输Ni(Ⅱ)动力学

采用2-乙基已基膦酸-2-乙基己基单醑(PC-88A)为载体,CHCl3为膜溶剂的大块液膜体系,研究了搅拌速度、载体浓度、pH、反应体系温度对镍离子传输的影响,测定了不同反应温度下的表观反应速率常数、镍离子在膜相中的最大值以及出现最大值的时间、镍离子在萃取与反萃取反应中进入和流出液膜的最大通量,获得了萃取与反萃取表观反应活化能分别为29.1和28.67 kJ·mol-1.结果表明,实验数据与理论值能够很好的吻合,镍离子的迁移过程可以以两个串联的准一级不可逆过程描述,在此实验条件下化学反应为控速步骤.     

烷基硫代磷酸钴的性能及钴镍分离研究

研究了酸度对二（２乙基己基）单硫代磷酸（Ｄ２ＥＨＭＴＰＡ）萃取Ｃｏ（Ⅱ）、Ｎｉ（Ⅱ）的影响，并与２乙基己基膦酸单（２乙基己基）酯［ＨＥＨ（ＥＨ）Ｐ］进行比较。用斜率法、等摩尔系列法及饱和法确定萃取平衡反应，通过在不同温度（５～３０℃）下分配比的测定，求得萃取反应的平衡常数Ｋｅｘ及热力学函数（ΔＨ°、ΔＳ°、ΔＧ°）。合成了固体配合物烷基硫代磷酸钴，并研究了其热稳定性能。     

Study on Transfer and Interfacial Kinetics of Neodymium and Samarium in Membrane Based Extraction

Ｔｈｅｅｘｔｒａｃｔｉｏｎｔｅｃｈｎｏｌｏｇｙｏｆｈｏｌｌｏｗｆｉｂｂｅｒｍｅｍｂｒａｎｅ (ＨＦＭ ) ,ｗｈｉｃｈｗａｓｄｅｖｅｌｏｐｅｄｉｎｅａｒｌｙ 1 980ｓ ,ｉｓａｎｅｗｋｉｎｄｏｆｓｅｐａｒａｔｉｏｎｍｅｔｈｏｄｃｏｍｂｉｎｅｄｐｒｏｃｅｓｓｅｓｏｆｌｉｑｕｉｄ -ｌｉｑｕｉｄａｎｄｍｅｍｂｒａｎｅｅｘｔｒａｃｔｉｏｎ .Ｔｈｉｓｍｅｔｈｏｄｃａｎｏｆ ｆｅｒｓｅｖｅｒａｌａｄｖａｎｔａｇｅｓｃｏｍｐａｒｅｄｗｉｔｈｃｏｎｖｅｎ ｔｉｏｎａｌｅｘｔｒａｃｔｏｒｓ[1～ 2 ] .Ｉｔｃａｎａｌｓｏｐｒｏｖ…     

Extraction kinetics of neodymium from chloride medium using HEH/EHP saponified with magnesium bicarbonate solution

Magnesium bicarbonate solution is considered as an environmentally friendly extractant saponification agent for the solvent extraction of rare earth elements due to its advantage of minimum water pollution.In order to reveal the extraction regularity, optimize production-process and guide the use of this new extraction system, the extraction of Nd(Ⅲ) in chloride medium with HEH/EHP saponified by magnesium bicarbonate solution was investigated with the self-designed constant interfacial area cell. Besides, the effects of stirring rate, temperature, specific interfacial area and concentration of Mg-HEH/EHP on the extraction rate of Nd(Ⅲ) were systematically investigated. Results show that, the rate of extraction is governed by both diffusion and chemical reaction, and the extraction reaction takes place at the interface. The apparent activation energy of the extraction reaction is 16.88 kJ/mol. The corresponding rate equation is deduced. The mechanisms and rate-determining step are speculated based on interfacial reaction models, which is consistent with the experimental results.     

Synergistic extraction of rare earth by mixtures of 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester and di-(2-ethylhexyl) phosphoric acid from sulfuric acid medium?

The extraction of Nd3 and Sm3 , including the extraction and stripping capability as well as the separation effect of Nd3 or Sm3 , from a sulfuric acid medium, by mixtures of di-(2-ethylhexyl) phosphoric acid (HDEHP, H2A2(0)) and 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (HEH/EHP, H2L2(0)) were studied. The distribution ratios and synergistic coefficients of Nd3 and Sm3 in different acidities were also determined. A synergistic extractive effect was found when HDEHP and HEH/EHP were used as mixed extractants for Sm3 or Nd3 . The chemical compositions of the extracted complex were determined as Nd·(HA2)2·HL2 and Sm·(HA2)2·HL2. The extraction equilibrium constants, enthalpy change, and entropy change of the extraction reaction were also determined.     

Synergistic extraction of cerium from sulfuric acid medium using mixture of 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester and Di-（2-ethyl hexyl） phosphoric acid as extractant

Synergistic extraction of cerium(IV) from sulfuric acid medium using mixture of 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester(HEH/EHP, HL) and Di-(2-ethyl hexyl) phosphoric acid (HDEHP, HA) as extractant was investigated. The results indicated that the maximum synergistic enhancement coefficients were obtained at the mole fraction of HEH/EHP=0.6, and cerium(IV) was extracted into organic phase in the form of Ce(SO4)0.5HL2A2. A cation exchange mechanism was proposed for the synergistic extraction of Ce(IV). The equilibrium constants and thermodynamic functions such as △G, △H, and △S were determined in the extraction of Ce(IV) from sulfuric medium using mixture of HEH/EHP and HDEHP.     

Synergistic extraction of rare earth by mixtures of 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester and di-（2-ethylhexyl） phosphoric acid from sulfuric acid medium

The extraction of Nd^3＋ and Sm^3＋, including the extraction and stripping capability as well as the separation effect of Nd^3＋ or Sm^3＋, from a sulfuric acid medium, by mixtures of di-（2-ethylhexyl） phosphoric acid （HDEHP, H2A2（0）） and 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester （HEH/EHP, H2L2（0）） were studied. The distribution ratios and synergistic coefficients of Nd^3＋ and Sm^3＋ in different acidities were also determined. A synergistic extractive effect was found when HDEHP and HEH/EHP were used as mixed extractants for Sm^3＋ or Nd^3＋. The chemical compositions of the extracted complex were determined as Nd.（HA2）2-HL2 and Sm.（HA2）2-HL2. The extraction equilibrium constants, enthalpy change, and entropy change of the extraction reaction were also determined.     

Synergistic extraction of rare earths by mixture of HDEHP and HEH/EHP in sulfuric acid medium

The extraction of RE（Ⅲ） （RE=La, Nd, Sm, Gd） in sulfuric acid medium using the mixture of HDEHP（H2B2） and HEH/EHP（H2L2） was investigated. The synergistic enhancement coefficient（R） was calculated for La （1.96）, Nd（3.52）, Sm（5.96）, and Gd（5.71）, respectively, at pH=2.0, and it was seen that the R increased with the increase of aqueous quilibrium pH. The configuration of the extracted complexes was considered to be RE（SOa）xH2x（HB2）3 with HDEHP, RE（SOa）xH2x（HL2）3 with HEH/EHP, and RE（HB2）2（HL2） with their mixture as the extractant with the slope method. The equilibrium constants and stability constants were calculated. A cation exchange mechanism was proposed as well.     

PEG-Na2SO4-CPAⅢ体系中镧、铀与钴的萃取分离

研究了Ｌａ（Ⅲ）、Ｕ（Ⅵ）等了了大聚乙二醇２０００（ＰＥＧ）－硫酸钠－偶氮氯膦Ⅲ（ＣＰＡⅢ）双水相体系中的萃取行为及存在形态。结果表明,在ＰＨ４．０－６．５的ＨＡｃ－ＮａＡｃ缓冲溶液中,Ｌａ（Ⅲ）、Ｕ（Ⅵ）几乎被ＰＥＧ相全部萃取,而Ｃｏ（Ⅱ）基本不被萃取,可实现Ｌａ（Ⅲ）与Ｃｏ（Ⅱ）及Ｕ（Ⅵ）与Ｃｏ（Ⅱ）混合离子的定量分离。经吸收光谱、摩尔经、连续浓度变换法、加入表面活性剂等试验表明,在萃取相中Ｌ     

高纯氧化钆的分离

本文以填充萃取剂２－乙基己基膦酸单２－乙基己基酯的ＣＬ－Ｐ５０７萃淋树脂为萃取色层的固定相，研究了在盐酸介质中淋洗液酸度、稀土负载量对分离钆的影响。对萃取色层柱效率与液－液萃取理论级数进行了比较，优化了工艺条件，分离出纯度大于９９．９９９７％的Ｇｄ２Ｏ３。     

Study on thorium recovery from bastnaesite treatment process

Thorium (Th) stripping behavior from HEH/EHP (2-(ethylhexyl) phosphoric acid mono-2-ethylhexyl ester) with H2SO4, HCl and HNO3 were investigated. The results indicated that H2SO4 was the most effective stripping reagent compared with HCl and HNO3. Selecting H2SO4 as the stripping reagent, the effect of phase ratio, acidity, H2SO4 amount, HEH/EHP concentration and Th loading in HEH/EHP on Th stripping were systematically investigated. As a result, the optimum stripping conditions of Th(IV) were obtained as the concentration of H2SO4 solution was 3.50 mol/L, phase ratio was 4:1. Low HEH/EHP concentration was benefit for Th stripping. Based on the results, pilot test for new Bastnaesite treatment process was carried out and the recovery of Ce, F and Th were more than 99%, 98% and 95% separately.     

中钇富铕稀土矿萃取分离新工艺研究

报道了萃取分离中钇富铕稀土矿新工艺，第一步La～Gd/(Gd)TbDy(HoY)/Ho～LuY萃取分离，出口水相La～Gd组份再Nd/Sm分组；中间出口的(Gd)TbDy(HoY)组份Tb/Dy分离。进行了扩大试验和工业生产应用。与中钇富铕稀土Nd/Sm先分组的传统工艺相比，处理能力提高约35%，P507存槽量减少约40%，贵重Tb、Dy稀土从第一步就出口，流程短、收率高。