TERNARY EXTRACTION MODELING USING THE REDLICH-KISTER EXPANSION

Mathematical models for liquid-liquid extraction processes are not widely available. The correlation of liquid-liquid equilibrium for such a model is often difficult. One correlation, based upon the Redlich-Kister expansion for the molar excess Gibb's free energy, has been shown to accurately represent ternary liquid-liquid equilibrium systems used in liquid-liquid extraction operations.

The use of this correlation in an extraction model was investigated and found to be suitable for a ternary liquid-liquid extraction model with only minor limitations. A successful ternary liquid-liquid extraction model was developed using this equilibrium correlation.     

番茄红素提取工艺的初步研究

番茄红素是一种具有抗癌活性的类胡萝卜素。本实验是番茄中提取番茄红素，研究了在不同的提取温度，时间，料液比，浸取液等因素下的提取效果，确定了最佳的浸取工艺条件。为进一步开发这种功能性天然色 素奠定了基础。     

MODELING OF SPEARMINT OIL EXTRACTION IN A PACKED BED USING SC-CO2

The packed bed extraction of spearmint oil using supercritical carbon dioxide was studied by a two-phase mass transfer model on the basis of desorption and diffusion. Unsteady-state mass balance for solute in supercritical and in solid phases led to two partial differential equations that were solved numerically using a linear equilibrium relationship. The model has four parameters, axial dispersion, mass transfer, and diffusion and desorption coefficients. Diffusion and desorption coefficients were used as the model tuning parameters and the others were predicted applying existing experimental correlations. The tuning parameters were calculated by the fitting error between 5 and 15% by the genetic algorithm method. In addition, this model was compared with a model that did not account for the desorption rate, according to the model suggested by Goodarznia and Eikani (G&E). Moreover, the effects of operational parameters such as pressures, temperatures, CO₂ flow rates, and mean particle sizes on the extraction yield were evaluated. In order to obtain experimental data for spearmint oil, a facility was designed and constructed to conduct the experimental part of this study. The two models were also applied to the literature's experimental data for rosemary leaves, grape seeds, peanuts, and tomato seeds. Comparison of the results of the proposed model with results from the G&E model indicated that the proposed model had better predictability. Also, good agreement of the proposed model results and the experimental data confirmed the basic hypothesis of the model and the importance of the desorption rate.     

MODELING ANALYTICAL TESTS OF SUPERCRITICAL FLUID EXTRACTION FROM SOLIDS WITH LANGMUIR KINETICS

A model for the analytical supercritical fluid extraction (SFE) tests from solid samples in which desorption of the solute from the surface of the solid is the rate determining step is presented. The desorption process is described by the Langmuir kinetics. The two stages of the test (static and dynamic) are modeled, where each of the two phases (solid and supercritical fluid) are considered well mixed. The resulting ordinary differential equations are solved analytically for the static stage and numerically for the dynamic stage. Dimensionless curves of concentrations of the two phases and fractional recovery during the two stages of the tests are predicted. These curves are characterized by two dimensionless parameters for the static stage, the equilibrium constant and the fractional initial capacity, in addition to one parameter for the dynamic stage, the desorption coefficient. The model provides a good fit to experimental results for SFE from solids. The trends in the fitted parameters with respect to pressure and temperature are in agreement with theory.     

从含钪氯化烟尘中提取钪

采用盐酸浸出、沉淀、萃取工艺,对从含钪氯化烟尘中提取钪的工艺进行了实验研究．结果表明：在最佳工艺条件下,钪的酸浸出率可达８２％以上,沉淀率及酸解度均接近１００％,萃取率可达９９．７％,反萃取率可达９９．６％,钪的总回收率约８０％．此工艺可有效地除铁、锰杂质,较好地实现钪与铁、锰杂质的分离．     

肟类萃取洁霉素的研究

本文首次将肟类萃取剂用于洁霉素的萃取，研究了其萃取规律.在中性及弱碱性条件下，所选用的氧肟－84、酮肟－85及N510三种肟类均可有效地萃取洁霉素，且在酸性条件下容易反萃.无论氧肟还是酮肟均按溶剂化历程萃取洁霉素，前者形成L.S型萃合物，后者形成L.2S型萃取合物（L－洁霉素，S－肟类萃取剂）.     

反胶团萃取蛋白质特性的研究

实验将一种阴离子表面活性剂（AOT）和一种阳离子表面活性剂（Aliquat336）分别溶于异辛烷（isooctane）中，构成了两种不同的反胶团体系．通过用两种不同的反胶团溶液萃取六种蛋白质的实验，研究了水相pH值及离子强度对反胶团体系中水含量Wo和蛋白质萃取率影响的规律．实验发现不论哪种反胶团体系，水相pH值对Wo的影响都不大，但pH值却对蛋白质萃取率有很大的影响，对AOT反胶团体系而言，随着pH值的降低，蛋白质的萃取率升高；对Aliquat336反胶团体系而言，随着水相pH值的降低，蛋白质的萃取率下降．随着离子强度的增大，AOT反胶团体系的水含量大幅度地降低；而对Aliquat336体系水含量的影响很小，但水相离子强度对蛋白质萃取率的影响是相同的，随着离子强度的增大，两种体系对蛋白质的萃取率均下降。     

嵌段式共聚物胶团在萃取分离中的应用

本文以嵌段式共聚物表面活性剂为对象，介绍了聚合物胶团概念、聚合物胶团的萃取分离作用原理和过程．讨论了聚合物表面活性剂加港特性以及萃取过程中放团再生等因素对萃取分离的影响．对聚合物胶团分离技术的研究将促进表面活性剂科学、膜分离技术的发展，在工业上具有良好的应用前景．     

用D_2EHPA-煤油溶剂萃取分离L-异亮氨酸

本文研究了从发酵液中用D2EHPA－煤油溶剂萃取分离L－异亮氨酸工艺．考察了萃取时pH值、萃取剂浓度和异亮氨酸浓度对于异亮氨酸和缬氨酸的萃取分配比的影响．在计算机上进行回归，得到以下分配模型：当1≤pH≤3．5时lgDIle＝0．09906pH2＋0．8625pH＋2．2696lgCHR－0．09188lg2CIle＋0．1766lgCIle－1．366lgDrmVal＝－0．0293pH2＋0．550pH＋1．2659lgCHR－0．2420lg2CIle＋0．4549lgCIle－1．696用此模型，应用分馏萃取理论，进行逐级计算，求取了萃取工艺的主要参数，并在φ20mm的多级离心萃取器上对上述结果进行了验证．结果表明：当CHR浓度为1．5mol／L，相比V：L：L’＝2：1：2，N’＝3，N＝6时，异亮氨酸的收率达到90％以上，纯度＞99％．实验取得了较为满意的结果．     

THE EXTRACTION BY N.N-DIALKYLAMIDES. II. EXTRACTION OF ACTINIDE CATIONS

ABSTRACT

N,N-dialkylamides are potential alternative extractants to tributyl-phosphate for the actinide separation in nuclear fuel reprocessing.

Extraction mechanisms of U(VI), Th(IV) and Pu(IV) from nitric acid media are investigated for the amide DOBA(((C₄H₉) (C₂H₅) CHCH₂)₂ NC(O) C₃H₇) and DO_iBA (((C₄H₉) (C₂H₅) CHCH₂)₂ NC(O) CH(CH₃)₂).

For low aqueous acidities, amides are neutral extractants. Extraction stoichiometrics of (Amide = DOBA or DO_iBA), have been established. Th(IV) is supposed to form a di- and a trisolvate in the inner-coordination sphere. For concentrated solvents, bilogarithmic dependences of distribution coefficients with ligand concentration point out non-integer slopes higher than those expected from stoichiometry. Such features, very often noted for amides, do not seem to be due to new chemical second-sphere species, which has never observed experimentally, but to polyoriented interactions between free ligands and complexes and may be considered as part of non-ideality.

Amides behave as anionic extractants with increasing acidity. New species are formed, involving UO₂(NO₃)₃ ^? and PU(NO₃)₆ ^2? anions, with the protonated amide ligands in the outer-coordination sphere of metals.     

THE KINETICS OF COBALT AND NICKEL EXTRACTION USING HEHEHP

The kinetics of the extraction of cobalt and nickel using purified mono 2-ethyl hexyl phosphonic acid mono 2-ethyl hexyl ester (HEHEHP) were studied using the Rotating Diffusion Cell (RDC) apparatus. The extraction of cobalt was Investigated over a wide range of cobalt concentration, extractant concentration, pH and temperature conditions. Nickel extraction was examined over a wide range of nickel concentrations.

The kinetic data were treated according to both interfacial and mass transfer with chemical reaction (MTWCR) models. The MTWCR model adequately described the kinetic data for both the cobalt and nickel extraction experiments. No variation of an interfacial model was adequate to describe the data. In the MTWCR model, the extraction rate was shown to be controlled by a mechanism involving diffusion of the extractant into the aqueous phase boundary layer with subsequent reaction involving the addition of the first ligand to the cobalt or nickel ion. This extraction mechanism was substantiated by supplementary results including the activation energy determination which indicated mixed diffusion and chemical reaction control, the significant measured rate of partition of the extractant to the aqueous phase, and the values of the cobalt and nickel complex formation constants in the aqueous phase.     

MEASUREMENT OF HOLDUP AND DROP SIZE DISTRIBUTION IN AN EXTRACTION COLUMN USING CONTINUOUS SAMPLING BY A CAPILLARY TUBE

A new method for hold-up measurement is described. Holdup in the column is calculated from the data on the phase ratio in the samples of the dispersion drawn-off from the column through a capillary at different sample flowrates. Local holdup and drop size distribution have been measured in a 50 mm ID vibrating plate column. It has been found that the drop size distributions at different agitation intensities are similar and that the dependence of the number density on the dimensionless drop volume can be described by the Gamma distribution.     

MODELING Cu EXTRACTION FROM ACIDIC SOLUTIONS USING P5100, PT5050, AND LIX 84

The Bureau of Mines studied the extraction of copper (II) from acidic sulfate solutions using commercial extractants LIX 84, P5100, and PT5050. Mathematical models, consisting of sets of nonlinear mass action and mass balance equations, were solved using a commercial equation-solving program on a personal computer. The models suggest that LIX 84 is a mixture of monomelic and dimeric extractant with an extraction equilibrium constant of 145 and a dimerization constant of 65 L/mol; PT5050 appears to be a monomeric extractant with an extraction equilibrium constant of 53; and P5100 shows more complex characteristics, with a monomeric extraction equilibrium constant of 400, a dimer formation constant of 3.7 L/mol, and a modifier-complex formation constant of 5.8 L/mol. For all models, the relative error of fit was less than 6%.     

MODELING AND CONTROL OF CONTINUOUS DIGESTERS USING THE PLS METHODOLOGY

The partial least squares (PLS) methodology is a regression tool able to deal with two important problems in system identification: the noise contained in the industrial data and the correlations that are observed among the input variables. In this article, the PLS technique is applied on real industrial data to produce dynamical multi-input single-output (MISO) models of the behavior of the kappa number in a continuous digester with respect to the important input variables that can be measured on-line. The ultimate goal is the development of a model predictive control (MPC) scheme that can be used for keeping the kappa number of the produced pulp close to the desired set point. We show that a modification in the standard MPC algorithm is needed in order to take into account the correlations among the input variables.     

丁烷物理发泡聚乙烯的生产与应用

介绍了一步法生产EPE材料的生产工艺、主要设备、主要原料和产品规格 ,并阐述了各类添加剂的作用机理 ,着重介绍了EPE的特点及应用     

用三烷基氧膦—煤油溶液从发酵滤液中萃取克拉维酸

报道了将中性磷这一高效萃取体系应用于克拉维酸的提取分离．研究了三烷基氧膦萃取克拉维酸的各种参数：ｐＨ、时间、相比、浓度等的影响，确定了最佳萃取条件及其工艺参数：３０％三烷基氧膦的煤油溶液为萃取剂，萃取平衡ｐＨ＝１．５，萃取相比Ｏ／Ａ＝１：３，并进行四级逆流萃取，饱和醋酸锂反萃，反萃平衡ｐＨ为７～７．５．     

LIQUID-LIQUID EXTRACTION IN A HOLLOW-FIBER DEVICE

Liquid-liquid extraction operations were conducted in a hollow fiber mass transfer device using two systems: phenol/water vs. n-octanol and phenol/hexane vs. water. Individual mass transfer resistances due to the tube-side fluid, the hollow fiber wall (membrane), and the shell-side fluid were determined for runs in which the solvent was held stagnant on the shell-side. Countercurrent flow runs with moving solvent were conducted to show that the degree of extraction rises steadily as the solvent-to-raffinate ratio increases. Factors affecting the mass transfer resistances in this type of device are discussed, and the advantages of hollow fiber units over conventional mixer-settler units are pointed out.     

SUPERCRITICAL EXTRACTION OF LINSEED OIL: ECONOMICAL VIABILITY AND MODELING EXTRACTION CURVES

The aim of the present study was to use supercritical technology to recover linseed oil (Linum usitatissimum L.) using carbon dioxide (alone or modified with ethanol as solvent) to determine the influence of the technique on the chemical composition of the oil obtained, model the kinetic curves of extraction, and estimate the manufacturing cost of the process. The experiments were conducted at 323 K, pressure of 25 MPa, constant solvent flow of 1.7 × 10^?5 kg/s, and extraction time of 5 h. The highest yield was obtained with the addition of cosolvent (28.8%). The SFE process of linseed oil manufacture proved to be economically viable, resulting in a product with a specific cost of 13.21 US$/kg_oil. As to oil composition, the main fatty acids detected were linolenic and oleic acid.     

钨钼混合溶液萃取平衡的测定与研究

采用一套溶剂萃取平衡测定装置,在酸性介质中,选择D2EHPA[二－（2－乙基己基）磷酸酯]为萃取剂,煤油为稀释剂,仲辛醇为改质剂,EDTA为络合剂,系统完整地测定了不同条件下两种浓度范围的含大量钨和少量钼的溶液的钨钼萃取分离平衡数据,分析和研究了各种因素对钨钼萃取分离的影响．分别用萃取平衡的经验模型和化学模型对该萃取体系进行了关联计算,得出了一套可以在工业计算中使用的经验模型和化学模型,为工业过程设计、工程优化和计算机模拟提供了基础．