SOLVENT EXTRACTION OP COPPER (II), NICKEL (II) AND COBALT(II) PROM HALIDE AND THIOCYANATE SOLUTIONS BY ALDOXIMES

The extraction of divalent copper, nickel and cobalt from acidic chloride solutions with solutions of heptaloxime, nonaloxime and 2-methyldekaloxime in toluene has been studied at 18*C.

These metals were found to be extracted according to the following solvation reaction:

The influence of syn-anti isomerization of aldoximes on the extraction has been discussed. Taking into account association and syn - anti isomerization constants of aldoximes in organic phase,hydration of extracted oomplexes and activities of salts in aqueous phase, effective extraction oonstants have been calculated for chloride solutions.

Separation of nickel and cobalt from aoidic chloride, bromide and thiooyanate solutions by extraction with heptaloxime has been studied.     

SOLVENT EXTRACTION OF COPPER(II) FROM CHLORIDE SOLUTIONS BY SOME PYRIDINE CARBOXYLATE ESTERS

n-octyl-3-pyridine carboxylate (NOPC), an analogue of the commercial reagent DS5443, was synthesized, and the stoichiometry of its reaction with copper(II) in chloride media was determined. At low metal loadings, copper(II) was extracted by the solvation reaction:

The factors affecting the separation of iron and copper from solutions containing copper(II),iron(II), and zinc(II)chlorides were determined in countercurrent extraction tests using DS5443.     

EXTRACTION OF COPPER(II) FROM ACID CHLORIDE SOLUTIONS BY N-DODECYL- AND N.N-DIHEXYLPYRIDINECARBOXAMIDES

ABSTRACT

N-dodecyl- and N,N-dihexylpyridinecarboxamides with amide group at 2, 3 or 4 position were synthesized. Model individual amides were used to recover copper(II) from chloride solutions at constant water activity and constant total concentration of dissolved species in aqueous solution. It was found, that pyridine-2-carboxamide forms with copper complexes (CuCl₂)_x (Ext)₂. Remaining amides form with copper complexes CuCl₂(Ext)₂. Monoalkylamides are not suitable for extraction because they and their complexes are slightly soluble in the hydrocarbon diluents. N,N-dialkylpyridinecarboxamides and their copper complexes are sufficiently soluble in the hydrocarbon phase to carry out extraction. However, they are strong extractants and extract efficiently copper already from dilute chloride solutions ([Cl] = 0.1 M). They extract also significant amounts of copper from concentrated (3-4M) nitrate solutions.     

SOLVENT EXTRACTION OF COBALT(II) WITH TRI-n-BUTYL PHOSPHATE FROM AQUEOUS-ORGANIC SOLUTIONS

Cobalt(II) has been extracted by 50% (v/v) TBP solution in benzene from HC1, HBr, and LiC1 solutions containing water miscible alcohols and nonbesic and basic aprotic solvents. All solvents used caused the distribution ratio of Co(II) to increase due to diminished water activity and shifts in equilibria of cobalt(II) complexes in solutions. Hexamethylphosphor-triamide (HMPTA) has been found to behave exceptionally in that it extracted Co(II) from LiC1 solutions into neat benzene and in the presence of TBP induced a weak synergism caused by extraction of at least two mixed solvates.     

THE BEHAVIOUR-STRUCTURE RELATIONS IN THE EXTRACTION OF COBALT(II), NICKEL(II), COPPER(II) AND CALCIUM(II) BY KONOACIDIC ORGANOPHOSPHORUS EXTRACTANTS

The reaction stoichiometrics were studied in the extraction of Co(II), Ni(II), Cu(II) and Ca(II) by n-octyl, 1-methylheptyl and 2-ethylhexyl hydrogen styrylphosphonates and di-2-ethylhexylphosphoric acid and 2-ethylhexyl hydrogen 2-ethylhexylphosphonate. The ultraviolet-visible and infrared spectra were recorded for these extractants and their complexes with the above metals. Based on the experimental data, an empirical relationship was established between the structure of the extractants and the extracting behavior: pH_½ = ApKa + Bν_p=0 - c where pKa and ν_p=0 are the acid dissociation constant of the extractants and the characteristic frequency of infrared absorption for the P=0 group, respectively. The values of A, B and C depend on the extracted metals. The analysis of the relationship between the steric effect of substituting groups and extracting power seems to indicate that the steric effect has been implied in the coefficients A, B and C.     

钴镍协同萃取体系

评述了自１９６６年以来报道的有关钴镍协同萃取的文献．主要介绍了磷酸、羧酸以及磺酸类萃取剂与含氮螯合萃取剂或非螯合萃取剂组成的协同萃取体系．此外，对一些由胺类萃取剂加磺酸或羧酸类萃取剂加吡啶羧酸酯组成的协同萃取也作了简单介绍．讨论了这些协同萃取体系萃取钴镍的反应机理、特点及其潜在的应用价值．     

SOLVENT EXTRACTION EQUILIBRIUM OF NICKEL FROM AMMONIACAL SOLUTIONS BY LIX 64N

Equilibrium data for the solvent extraction of nickel from amraoniacal solutions by LIX 64N (10 vol%) dissolved in kerosene (15% aromatic content) are reported. The effect of NH3/aq) concentration, LIX 64N concentration, pH and temperature are shown. The stoichiometry of the Ni-active oxime in LIX 64N complex was ascertained by spectrophotometry studies. A mathematical mechanistic model was developed for the prediction of extraction distribution coefficients as a function of pH. The model predicts more accurate results at high pH values, as could be expected taking into consideration the assumptions made in developing the model.     

SOLVENT EXTRACTION OF PALLADIUM FROM CHLORIDE SOLUTIONS BY ALKYLAMMONIUM DI(2-ETHYLHEXYL)DITHIOPHOSPHATES

ABSTRACT

The extraction of palladium (II) from chloride solutions (over a wide region of aqueous acidity) by di(2-ethylhexyl)dithiophosphates of tetraoctylammonium, tri-n-octylammonium and di-n-octylammonium in toluene at the constant chloride concentration has been studied. A synergistic effect was shown to be observed in these systems and it is explained by the formation of unusual complexes with mixed ligands. It has been established the palladium complexes, such as (R₃NH)[PdCl₂A], (R₃NH)[PdCl₂A] and (R₂NH₂)[PdCl₂A], involving both alkylammonium cation and dialkyldithiophosphate anion are extracted under conditions of the loaded organic phase using distribution methods depending on a composition of aqueous and organic phase. At the excess of R₃NHA or R₂NH·HA, PdA₂ is extracted into the organic phase. Table 8 reports the results obtained and indicates the domains of existence of the various species of palladium (II) extracted into the organic phase in the binary ex-tractant systems in comparison with the initial systems     

SOLVENT EXTRACTION OF SILVER(I) AND MERCURY(lI) BY O,O-DI-n-BUTYL PHENYLAMINO-PHENYLMETHANETHIO PHOSPHONATE FROM CHLORIDE SOLUTIONS

The extraction of Ag(I)and Hg(II) from chloride solutions of constant ionic strength (lM) by O,O-di-n-butyl a -phenylamino--phenylmethanethiophosphonate dissolved in trichloromethane has been studied. The extraction dependences of metals on the ligand, hydrogen and chloride ions concentrations have been analysed to determine the stoichiometry of the extracted complexes and their equilibrium constants.

Evidence was found for the formation of the complexes     

COPPER EXTRACTION FROM CHLORIDE SOLUTIONS WITH MIXTURES OF SOLVATING AND CHELATING REAGENTS

ABSTRACT

Equimolar mixtures of N,N,N',N'-tetrahexylpyridine-3,5-dicarboxamide (L) with 2-hydroxy-5-t-octylbenzophenone oxime or l-phenyldecane-l,3-dione (HB), were used to extract copper from chloride solutions of various concentration of chloride ions. Chloride ions were then scrubbed out with water or ammoniacal solutions and copper was transferred from the solvate CUCl₂L₂ to chelate CuB₂- Both studied systems permit effective extraction of copper and removal of chloride ions from the organic phase. Some protonation of solvating reagent L occurs, however, when copper is stripped from the chelate with hydroxyoxime. This negative effect can be suppressed when 1-phenyl decane-1,3-dione is used as a chelating agent. The scrubbing of chloride ions must be then carried out with ammoniacal solutions to avoid simultaneous stripping of copper.     

SOLVENT EXTRACTION OF ZINC(II) BY ORGANOPHOSPHORUS ACIDS COMPOUNDS FROM PERCHLORATE SOLUTIONS.

ABSTRACT

The extraction of zinc from perchlorate solutions at 0.1 mol.dm^?3 of ionic strength by di(2-ethylhexyl)phosphoric acid (HDEHP), 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) and di(n-octyl)phosphinic acid (H[DOP]) dissolved in toluene has been studied at 25 ° C.

The distribution coefficient was determined as a function of pH and HA concentrations and the data were analyzed both graphically and numerically using the computer program LETAGROP-DISTR.

The results showed that the data can be explained assuming the formation of ZnA₂(HA)₂ and ZnA₂HA in organic phase for all the extractants used. A correlation between extracted species and concentration of the various extractants has been found.

The predominance of the different species into the organic phase has been correlated with the difference between their extraction constants.

The anion of the ionic medium is not extracted into the organic phase.     

PHYSICAL CHEMISTRY OF ADSORPTION OF COPPER,NICKEL AND COBALT ON LIGNITE FROM AMMONIACAL SOLUTIONS

The adsorption of Me(metal),NH_3 and CO_2 on lignite from ammoniacal solution containing metallicions such as Cu,Ni,and Co was investigated.Preliminary mechanism studied revealed that active carboxyland phenolic groups of humic acid in lignite as well as surface adsorption were involved.The rate of ap-proach to adsorption equilibrium on lignite was NH_3>Ni>Co>Cu andthe adsorption on lignite is Cu>Co>Ni>NH_3.The order of selective elution was NH_3>>Ni,Co>Cu.All metals were fully stripped and NH,could only be recovered partially.NH_3 adsorbed on lignite fron metal-ammoniacal solution is easily lost by volatilization,only a smallfraction remaining on lignite at a temperature of 120℃.CO_2 adsorbed physically in nature from ammonia-cal solution with a capacity of less then one percent was observed under the practical conditions generallyin hydrometallurgy.     

EXTRACTION OF COPPER FROM ACID CHLORIDE SOLUTIONS BY N-ALKYL-AND N,N-DIALKYL-3-PYRIDINECARBOXAMIDES

ABSTRACT

Model individual N-alkyl-3-pyridinecarboxamidee and N,N-di-alkyl-3-pyridinecarboxamides were synthesized and used for copper(II) extraction from chloride solutions. The stoichiometry of its reaction with copper(II) in chloride media was determined. N-alkyl-3-pyridinecarboxamides are stronger extractanta than N,N-dialkyl-3-pyridinecarboxamides but N-alkyl-3-pyridinecarboxamides and their complexes are slightly dissolved in the hydrocarbon diluents.     

SOLVENT EXTRACTION EQUILIBRIA OF TRIS(BENZOYL- TRIFLUOROACETONATO)COMPLEX OF COBALT(II) AND NICKEL(II) AS ION-PAIRS WITH TETRABUTYLAMMONIUM

Abstract

Solvent extraction of cobalt(Il) and nickel(II) in aqueous 1 mol dm^?3 NaCl solutions with benzoyltrifluoro-acetone(Hbfa) in carbon tetrachloride has been measured in the absence and presence of tetrabutylammonium(tba⁺). In the absence of tba⁺, M(bfa)₂ species is extracted and the extraction of cobalt(II) is better in the higher Hbfa concentration range but in the presence, M(bfa)₃ ^?tba⁺ type ion-pair is extracted and the extraction of nickel-(II) is always better. This is explained in terms that although the bis-nickel(II) complex is more stable, it is much more strongly hydrated than the bis-cobalt(II) complex and consequently its extraction is hindered but in the tris-complexes such a large difference of the hydration may not occur and the more stable nickel(II) complex is extracted better.     

SOLVENT EXTRACTION OF COPPER (II) WITH AN ALDOXIME FROM HYDROCHLORIC AND HYDROBROMIC ACIDS

2-ethylhexanal oxime was synthesized to examine the selectivities for various metals in the extractions from hydrochloric acid. It was found to be highly selective for palladium(II) over platinum(II and IV) and other base metals including copper(II), zinc and aluminum, especially in the low concentration region of chloride ions.     

AGGREGATION BEHAVIOR OF COBALT(II), NICKEL(II), AND COPPER(II) BIS(2-ETHYLHEXYL) PHOSPHATE COMPLEXES IN n-HEPTANE

ABSTRACT

The solution behavior of divalent transition metal-bis(2-ethylhexyl) phosphate (M(DEHP)₂, M = cobalt, nickel or copper) complexes in n-heptane have been investigated by vapor pressure osmometry, viscometry and dynamic light scattering. Co(DEHP)₂ complexes tend to form large macromolecular species with a mean aggregation number N_agg as large as 225, and the size of the macromolecular species decreases with increasing Co(DEHP)₂ concentration. In contrast, Cu(DEHP)₂ complexes tend to form small macromolecular species N_agg = 4-8 which increase in size with increasing Cu(DEHP)₂ concentration. On the other hand, Ni(DEHP)₂ complexes (and Ni(DEHP)₂-2H₂O complexes when the molar ratio of H₂O     

EXTRACTION CHEMISTRY OF COBALT AND NICKEL BY DI(1-METHYLHEPTYL)PHOSPHINIC ACID

The fundamental characteristics and mechanism of extraction of cobalt (II) and nickel(II) by di-(1-methylheptyl) phosphinic acid (DMHPA) were studied. The extraction ability of cobalt(II), nickel (II) and various metals by DMHPA decreases in the order Fe(III) > Zn ? Pb(II) > Mn(II) > Cu(II) > Co(II) > Mg > Ca > Ni(II). The difference of the pH_½ values for nickel and cobalt reaches 2.06 pH units, which is apparently greater than those from extraction by di(2-ethylhexyl)phosphoric acid (DEHPA)and 2-ethyl-hexyl ester 2-ethylhexylphosphonic acid(DHEHPA).The slope analysis and IR spectroscopy reveal that the stoichiometrics of cobalt and nickel extracted species are Co(HA₂)₂ and Ni(HA₂)₂(H₂O)₂ respectively. As demonstrated by the study of the electronic spectroscopy the structure of the extracted complexes were shown as tetrahedral and octahedral configuration respectively. Furthermore, the coordination field parameters of the complexes were calculated.     

SOLVENT EXTRACTION OF LEAD BY TRILAURYLAMMONIUM CHLORIDE DISSOLVED IN TOLUENE FROM DIFFERENT CHLORIDE MEDIA

The extraction of Pb(II) from chloride solutions by trilaurylammonium chloride (TLAHC1) dissolved in toluene has been studied by metal distribution measurements. The work has been performed at three different aqueous chloride concentrations (1.0, 2.0 and 3.0 mol.dm^?3NaCl). The treatment of the experimental data at each chloride concentration agrees with the stoichiometry of the extracted metal species in the organic phase while the values of their equilibrium constants are different for the various chloride concentrations. The extraction process is explained by the following extraction reactions

The corresponding logarithmic values of K₂and K₅at the different chloride concentrations, I, are: K₂K₅, I; 4.62, 8,51, 1.0; 4.54, 8.38, 2.0; 4.48, 8.32, 3.0. The values obtained have been correlated by using the Specific Interaction Theory (S.I.T.) and the interaction coefficient for the Pb²⁺,Cl^?ions as well as the thermodynamic constants, Kn⁰, have been determined.     

LIQUID-LIQUID EXTRACTION OF GOLD(III) AND ITS SEPARATION OVER COPPER(II), IRON(III), AND ZINC(II) USING THIOUREA DERIVATIVES FROM CHLORIDE MEDIA

ABSTRACT

Selective liquid-liquid extraction of Au(III) from aqueous chloride media (1 mol/L NaCl) into cumene by thiourea derivatives namely 2a-c (N-thiocarbamoylbenzamidine derivatives), 3a-f (N-benzoylthiourea derivatives) has been investigated in detail. Marked differences in the metal extraction are noted using these organic compounds with respect to their structural variation. The extraction behaviour of Au(III) with extractants 2a-c and 3a-f followed the order : 2b> 2a>2c and 3e≈ 3c≈ 3d >3a >3f≈3b, respectively. The organic reagent 2a and 3c were selected for further detailed studies owing to their better strippability behaviour. Optimum conditions such as structure of the organic extractant, aqueous phase pH, diluent, time of equilibration, metal concentration, extractant concentration, effect of other metal cations were established for extraction separation of Au(III). Experimental data have been treated graphically and numerically by means of the computer programme LETAGROP-DISTR, and can be explained by assuming the formation of the species AuCl₃L and AuCl₃L₂ for 2a-c and AuCl₃L₂ for 3a-f derivatives. The lack of interference from even appreciable amounts of possible base metals such as Cu(II), Zn(II) and Fe(III) may be considered an outstanding advantage of the method for separation of gold from these metals using 2a and 3c.     

EXTRACTION KINETICS OF COPPER BY TRILAURYLAMMONIUM CHLORIDE IN TOLUENE FROM AQUEOUS CHLORIDE MEDIA

Abstract

The rate of extraction of copper(II) from aqueous chloride solutions by tri-n-laurylammonium chloride (TLAHC1) dissolved in toluene has been investigated. The extraction rate was evaluated as function of the chemical composition of the system. The experiments were performed by using a stirred cell with constant inter-facial area. The experiments were performed at a stirring rate of the two phases where the influence of film diffusion is minimized. The data have been interpreted by a mechanism which assumes interfacial chemical reactions between the bulk species containing copper(II) and the molecules of TLAHC1 absorbed at the interface as rate determining.