High-speed Computers as a Supplement to Graphical Methods. 12. Application of LETAGROP to Data for Liquid-liquid Distribution Equilibria.

Liem, Djiet Hay; Christian, Sherril D.; Grundnes, Just; Roach, Stephen R.; Engebretsen, Jan E.; Ehrenberg, L.

doi:10.3891/acta.chem.scand.25-1521

Cited by 192 publications

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“…The developed model consists of a set of massaction equilibrium equation plus the appropriate mass-balance equations. The valué of the equilibrium constant was calculated by treatment of experimental data by the program LETAGROP-DISTR (17). This program minimizes the sum of the squares defined as:…”

Section: Resultsmentioning

confidence: 99%

Modeling of solvent extraction equilibrium of Cu(II) from sulphuric Acid solution with MOC-55TD

Alonso¹

1999

REVMETAL

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Resumen The extraction of Cu(II) from acidic sulphate aqueous solutions using the commercial MOC-55TD extractant is studied. A predictive model, which consists in a set of non-linear mass action and mass balance equations is proposed. The model was solved using a tailor-made equation-solving program. The extraction of copper can be described by the formation of CuR 2 species (log K ext = 0.717 ± 0.03) in the organic phase. The copper equilibrium isotherm was also obtained at 20 °C.Palabras clave: Solvent extraction. Modelling. Copper. MOC-55TD.Modelización del equilibrio de extracción con disolventes cobre-MOG-55TD en disoluciones de ácido sulfúrico Abstract Se estudia la extracción de Cu(II) de disoluciones acuosas acidas, en medio sulfato, mediante la oxima comercial MOC-55TD. Se propone un modelo para predecir la extracción del metal; este modelo consiste en una serie de ecuaciones no lineales de acción de masas y balance de masas. El modelo se resolvió empleando un programa de ordenador específicamente definido para este tipo de equilibrios. La extracción de cobre se describe por la formación de la especie CuR 2 (log ^e xt = 0,717 ± 0,03) en la fase orgánica. Se ha obtenido la isoterma de extracción de cobre a 20 °C.

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Section: Resultsmentioning

confidence: 99%

Modeling of solvent extraction equilibrium of Cu(II) from sulphuric Acid solution with MOC-55TD

Alonso¹

1999

REVMETAL

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“…(2) to establish the speciation of the system, the distribution data were analyzed numerically using the computer program LETAGROP-DISTR. 15 In these calculations a set of species are assumed to exist and their formation constants are determined by minimizing the error square sum, U, defined by U= pv(log Dca,-log Dexp)2,…”

Section: Resultsmentioning

confidence: 99%

Synergistic Effect of Tartaric Acid in the Extraction of Iron(III) from Aqueous Nitrate by Di(2-ethyl hexyl)phosphoric Acid in Hexane

et al. 1990

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The addition of tartaric acid to aqueous nitrate solutions containing Fe(III) produces an increase in the solvent extraction of Fe(III) by di(2-ethyl hexyl)phosphoric acid, DEHPA, in hexane solutions. This effect has been studied and it is explained in terms of chemical equilibrium between the two liquid phases by applying the following reactions: Fe3++L2-= FeL+; eq. const. log 13=7. Iron(III) is known to be extractable by alkylphosphoric acids (HA).' Information concerning the speciation of this system is wide and varies according to different authors.2-' Thus, while Baes2,3 suggests the formation of FeA3(HA)3 and Fe3A8C104 species, Sato and coworkers4'5 report species FeA3(HA)3 and Fe2Al0H4 regarding the extraction of Fe(III) from hydrochloric acid solutions. In a recent study Fe(III) was determined to form different metal extracted species (FeA3(HA)3, Fe2A3(HA)s and Fe3A3(HA)3) in the organic phase.8The extraction efficiency may be enhanced by using an appropriate mixture of organic extractants.9 Also, the complexation of metal ions in the aqueous phase contributes to a modification of the extraction process which, in general, is reduced by such aqueous reactions. On the other hand, it is known that metal citrates and tartrates can be extracted as anionic chelate compounds. 10 In our case, Fe(III) forms stable aqueous complexes with tartrate 1 which prevents the precipitation of Fe(III) hydroxide, even at high pH values. Surprisingly, extraction enhancement of Fe(III) by di(2-ethyl hexyl)-phosphoric acid-hexane solutions has been observed in presence of aqueous tartaric acid. In the present work, this phenomenon was studied in order to elucidate the chemical reactions involved. ExperimentalReagents, solutions and apparatus Iron(III) nitrate (Merck, analytical reagent grade (A.R.)) was used to prepare stock solutions in 0.5 M N03-. The Fe3+ content and free acid were determined by standard procedures.12"3 NaNO3 (Probus, A.R.) was purified and stored (described in ref. 14) and was used as to maintain a constant ionic strength at 0.5 M. An 59Fe(N03)3 radioactive stock solution was prepared from the corresponding iron(III) citrate salt (supplied by General Radioquimica S.A.) of 0.2 mCi/ml activity and was used in radiotracer analysis.Tartaric acid (Industrias Quimicas y Tartaricas S.A., A.R.) was used to prepare stock solutions in 0.5 M NaNO3; its purity was determined by acid-base titrations.Solutions of HNO3 in 0.5 M N03-were employed to modify the pH of the aqueous solutions. The pH of aqueous solutions was measured by a pH-meter (Crison) and a calibrated combined glass electrode.Solutions of di(2-ethyl hexyl)phosphoric acid, DEHPA (HA), were prepared from DEHPA (BDH) in hexane (Probus, A.R.).The y-activities of radioactive solutions were measured with a well-type NaI scintillation counter (Berthold BF 2306).UV measurements were carried out with a Shimadzu spectrophotometer.

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“…For many of the papers thatused numerical methods, unspecified curve-fitting routines were used to model specific equilibrium expressions. The following computer programs have been designed specifically for analyzing solventextraction equilibria: LETAGROP-DISTR (Liem 1971), MODEX (Noirot and Wozniak 1985), and SXLSQA (Baes et al 1990). …”

Section: Introductionmentioning

confidence: 99%

The SX Solver: A New Computer Program for Analyzing Solvent-Extraction Equilibria

McNamara¹,

Rapko²,

Lumetta³

1999

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High-speed Computers as a Supplement to Graphical Methods. 12. Application of LETAGROP to Data for Liquid-liquid Distribution Equilibria.

Cited by 192 publications

References 0 publications

Modeling of solvent extraction equilibrium of Cu(II) from sulphuric Acid solution with MOC-55TD

Modeling of solvent extraction equilibrium of Cu(II) from sulphuric Acid solution with MOC-55TD

Synergistic Effect of Tartaric Acid in the Extraction of Iron(III) from Aqueous Nitrate by Di(2-ethyl hexyl)phosphoric Acid in Hexane

The SX Solver: A New Computer Program for Analyzing Solvent-Extraction Equilibria

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