磷酸的溶剂萃取法净化

在全面调研国内外现有的湿法磷酸净化技术的基础上,实验比较了不同萃取剂(正丁醇、TBP、异丁醇和异戊醇)对于磷酸萃取的效果,结果表明,正丁醇对磷酸的萃取效果最好,温度的提高会使磷酸在两相的分配系数略有下降. 溶剂萃取磷酸主要以分子形式进行,因此无机强酸的加入有利于提高磷酸在两相的分配. 比较了正丁醇萃取纯磷酸和粗磷酸的差别,分析了其原因. 正丁醇对金属离子几乎没有萃取效果,因此,溶剂法可以作为一种有效的净化磷酸的方法.     

溶剂萃取法净化湿法磷酸的新进展

综述了湿法磷酸净化的常用方法及优缺点,介绍了典型的溶剂萃取法工业流程以及国内外的研究现状,详细介绍了由四川大学和贵州宏福实业开发有限总公司共同开发的新型湿法磷酸净化技术,该技术流程短,成本和能耗低,有广阔的应用前景。     

我国溶剂萃取法净化湿法磷酸新技术的开发

溶剂萃取法湿法磷酸净化技术是目前世界上先进的工业磷酸生产技术,与以黄磷为原料生产的工业磷酸相比,能耗低、投资省、污染少。介绍了我国溶剂萃取法净化湿法磷酸新技术开发的主要内容包括以稀磷酸为原料,采用一种混合萃取剂,深度脱硫在萃取后的有机相中进行,并率先把振动筛板塔应用于湿法磷酸净化工艺,经过1kt/a的中间试验和10kt/a的小型工业试验,已建成的50kt/a湿法磷酸净化装置也已连续运行,主要技术经济指标达到国际先进水平,具有推广价值。     

溶剂萃取法净化湿法磷酸国内近况

综述了湿法磷酸净化的常用方法及优缺点,介绍了典型的溶剂萃取法工业化流程以及国内外的研究现状,着重阐述了由四川大学和贵州宏福实业开发有限总公司共同开发的溶剂萃取法净化湿法磷酸的工艺流程和技术特点,认为该工艺的流程短、投资少、生产成本低,SO4^2-：脱除彻底,P2O5,利用率高、能耗低,具有自主知识产权,应用前景广阔。     

有机磷(膦)酸对碱土金属的萃取

Solvent extraction equiliria of four main alkaline earth metals (magnesium, calcium, strontium and barium) with di(2-ethylhexyl) phosphoric acid (DEHPA), 2-ethylhexyl phosphonic acid mono-(2-ethylhexyl) ester, di(2,4,4-tri-methylpentyl) phosphinic acid and IR spectra of the extracts have been studied. The selectivity order is dependent of the e/r value and hydration energy of the metal ions. The minor shift of the P→O in IR absorption of the alkaline earth metal extracts indicates that the interaction between the metal ions and P→O is much weaker for alkaline earth metals than for transitional metals. The distribution of the four alkaline earth elements between aqueous solutions and solutions of DEHPA and neutral organophosphorus compunds, tri-n-butyl phosphate (TBP) or tri-octyl phosphine oxide (TOPO) in kerosene have been determined at varying ratio of TBP or TOPO to DEHPA and the positive synergism is observed. The synergic effects is explained by using IR spectra of the loaded organic phase.     

湿法磷酸溶剂萃取法工艺的研究

研究了溶剂萃取法净化湿法磷酸的工艺。试验结果表明,以异丙醚和磷酸三丁酯作为萃取剂对用硫酸分解磷矿制得的浓缩磷酸进行了多级逆流萃取及反萃取,可以得到高浓度净化磷酸。该工艺具有较好的经济效益,为湿法磷酸的净化提供了一条较好的途径。     

钨萃取平衡分配比的研究

使用一套溶剂萃取平衡的试验装置,选择膦酸三丁酯（ＴＢＰ）为萃取剂,苯为稀释剂,系统地测定了钨的溶剂萃取平衡及萃取条件对萃取平衡分配的影响,可为工业过程设计、工程优化和计算机模拟提供依据。     

Synergistic Solvent Extraction and Transport of Zn(II) and Cu(II) across Polymer Inclusion Membranes with a Mixture of TOPO and Aliquat 336

Separation of zinc(II) and copper(II) ions from aqueous solutions by synergistic extraction and transport through polymer inclusion membranes (PIMs) has been investigated. A mixture of trioctylphosphine oxide (TOPO) and trioctymethylammonium chloride (Aliquat 336) was used as a selective extractant as well as an ion carrier in polymer membranes. The effects of hydrochloric acid concentration in the aqueous phase and extractants concentration in the organic phase on the separation process of zinc(II) and copper(II) ions have been studied. Zn(II) ions were successfully separated from Cu(II) ions in solvent extraction process using 0.025 M TOPO and 0.06 M Aliquat 336 in kerosene. Polymer inclusion membranes (PIMs) containing a mixture of TOPO and Aliquat 336 as the ion carrier have been prepared and the facilitated transport of Zn(II) and Cu(II) ions has been studied. The influence of membrane composition on the transport kinetic of Zn(II) and Cu(II) has been evaluated. Zn(II) ions were preferably transported from the aqueous solutions containing Cu(II) and above 87% of Zn(II) ions were effectively recovered from the 0.5 M HCl solution as the source phase through PIM into 0.5 M H₂SO₄ as the stripping phase.     

仲辛基苯氧乙酸萃取Zn(II)的性能

研究了一种新型萃取剂仲辛基苯氧乙酸(CA–12)的皂化以及从盐酸介质中萃取Zn(II)的性能. 考察了萃取温度、平衡水相酸度、萃取剂浓度等因素对萃取的影响. 氨水皂化CA–12的最佳条件是使用含有1.0 mol/L NaCl的稀氨水制皂、皂化率为80%；分配比随平衡水相酸度的增加而减小，且lgD与pH呈线性关系，其斜率约为2；分配比随萃取剂初始浓度的增大而增大；初始酸度pH=6.0~6.5、萃取剂初始浓度CHA>0.10 mol/L时，水相中0.01 mol/L Zn(II)几乎被定量萃取. 计算得到了CA–12从盐酸介质中萃取Zn(II)的过程热效应DH=3.28 kJ/mol.     

溶剂萃取法从氟硅酸中除砷的研究

选用某几种中性磷类萃取剂和胺类萃取剂,助萃剂,磺化煤油稀释剂,对用溶剂萃取法除去氟硅酸中的砷展开基础性研究,寻找合适的萃取剂及相关工艺条件。     

溶剂微胶囊--现代萃取技术发展的核心之一

从溶剂微胶囊的制备及应用两方面较为全面地综述了溶剂微胶囊技术的发展,并总结了其特点,提出技术展望。溶剂微胶囊技术是微胶囊技术与萃取技术相结合而发展起来的新型分离技术,溶剂微胶囊具有萃淋树脂可以有效避免乳化和分相容易等优点,而在萃取剂包覆量和防止萃取剂流失方面,具有更明显的优势。     

溶剂萃取法净化湿法磷酸的研究

研究了在用磷酸三丁酯作为主要萃取剂时萃取塔的结构参数和操作参数对萃取效率的影响，比较了洗涤条件对杂质离子的脱除效果，以及不同条件下反萃效果的差异。实验结果表明：萃取效率不会随着振动频率的增大而增大，当萃取酯中有夹带酸时振动频率越小萃取率就越大，萃取塔筛板间距为5．5cm时萃取效果最好；铵盐和钠盐的脱除硫酸根离子能力大致相同，加大它们的浓度或缩小洗涤相比有利于脱除硫酸根离子，反萃取操作容易。     

哌啶多氮衍生物对银溶剂萃取性能的研究

合成了一种新萃取剂哌啶多氮衍生物。在PH为 5 5醋酸～醋酸钠的缓冲溶液中 ,以二氯甲烷为溶剂 ,用 10× 10 - 6 mol/L新萃取剂哌啶多氮衍生物可将 2 0× 10 - 6 mol/L的银完全萃取出来。     

磷酸三丁酯和二异丙醚溶剂萃取体系脱除湿法磷酸中氟的研究

以磷酸三丁酯与二异丙醚为溶剂,采用溶剂萃取法脱除湿法磷酸中的氟。研究了萃取剂中TBP的体积分率、相比、萃取时间、搅拌转速、反萃剂加入量对氟的净化效果的影响,确定了磷酸三丁酯与二异丙醚混合溶剂体系脱氟的工艺条件。结果表明:萃取剂组成为TBP与二异丙醚体积比为1∶1;相比4∶1、萃取时间为5min、搅拌转速为300r/min、反萃剂加入量为萃取相体积的10%,在此条件下,磷酸三丁酯与二异丙醚萃取体系对氟离子有较好的分离能力。     

Neutron Polarization Analysis for Biphasic Solvent Extraction Systems

We performed neutron polarization analysis (NPA) of extracted organic phases containing complexes, comprised of Zr(NO₃)₄ and tri-n-butyl phosphate, which enabled decomposition of the intensity distribution of small-angle neutron scattering (SANS) into the coherent and incoherent scattering components. The coherent scattering intensity, containing structural information, and the incoherent scattering compete over a wide range of magnitude of scattering vector, q, specifically when q is larger than q* ≈ 1/R_g, where R_g is the radius of gyration of scatterer. Therefore, it is important to determine the incoherent scattering intensity exactly to perform an accurate structural analysis from SANS data when R_g is small, such as the aforementioned extracted coordination species. Although NPA is the best method for evaluating the incoherent scattering component for accurately determining the coherent scattering in SANS, this method is not used frequently in SANS data analysis because it is technically challenging. In this study, we successfully demonstrated that experimental determination of the incoherent scattering using NPA is suitable for sample systems containing a small scatterer with a weak coherent scattering intensity, such as extracted complexes in biphasic solvent extraction systems.     

Application of Single-Ion Activity Coefficients to Determine the Solvent Extraction Mechanism for Components of High-Level Nuclear Waste

Abstract

The TRUEX solvent extraction process is being developed to remove and concentrate transuranic (TRU) elements from high-level and TRU radioactive wastes that are currently stored at U.S. Department of Energy sites. Phosphoric acid is one of the chemical species of concern in the application of solvent extraction processes for removal of actinides, for instance at the Hanford site, where bismuth phosphate was used to recover plutonium.

The mechanism of phosphoric acid extraction with TRUEX-NPH solvent at 25°C was determined from phosphoric acid distribution ratios, which were measured by using a phosphoric acid radiotracer and a variety of aqueous phases containing different concentrations of nitric acid and nitrate. A model was developed for predicting phosphoric acid distribution ratios as a function of the thermodynamic activities of nitrate ion, and hydrogen ion. The Generic TRUEX Model (GTM) was used to calculate these activities based on the Bromley method. The derived model supports extraction by CMIO and TBP in TRUEX-NPH solvent of a phosphoric acid-nitric acid complex and a CMPO-phosphoric acid complex.     

丙酮酸化学萃取的盐效应

以三辛胺为萃取剂,在不同离子类型及离子强度下对丙酮酸的络合萃取过程进行了研究。结果表明,在一定pH范围内,随无机离子浓度的增加,丙酮酸分配系数随盐浓度的增加而迅速降低;萃后水相pH随盐浓度的增加均有不同程度的升高,在同一离子强度下,萃取剂浓度越高,萃后水相pH上升幅度越大。红外光谱的分析结果证实了无机阴离子可能通过同离子竞争,抑制了丙酮酸根离子与络合剂的离子对缔合作用,从而降低了萃取效果。