Solvent Extraction Of Cobalt Research Articles

Solvent extraction of cobalt(II) ions; cooperation of oximes and neutral donors

2-Hydroxy-1-naphthaldoxime (HL 1) and 1-hydroxy-2-naphthaldoxime (HL 2) have been synthesized and their extractive properties towards cobalt(II) ions from sodium chloride aqueous phase into dichloromethane were studied. The presence of neutral donors tri- n-octylphosphine oxide (TOPO), tributylphosphate (TBP), tris(2-ethylhexyl)phosphate (T2EHP), tributylamine (TBA), trioctylamine (TOA) and dimethylsulfoxide (DMSO) shifts the extraction percentage curves towards lower pH region, indicating a synergistic effect of these donors on the extraction of cobalt ions by the studied oximes. The examined amines present significantly higher synergistic effect in comparison with TOPO, TBP, T2EHP and DMSO donors. It is shown that the stoichiometry of adducts formed in the organic phase by both HL 1 and HL 2 in the presence of TOPO depends on the oxime concentration. This stoichiometry was found to be [Co(L 1(2))(TOPO)Cl] and [Co(L 1(2)) 2(TOPO)] at low and high concentration of the oximes, respectively.

Effect of Temperature on The Solvent Extraction of Cobalt(II), Nickel(II), and Copper(II) Metal Ions by o-diphenylamino Benzoic Acid

Effect of Temperature on The Solvent Extraction of Cobalt(II), Nickel(II), and Copper(II) Metal Ions by o-diphenylamino Benzoic Acid

Liquid–liquid extraction of Cu(II), Co(II) and Ni(II) with salicylidèneaniline from sulphate media

For a fundamental study on the development of novel extraction divalent metal, the extraction behaviour of copper(II), cobalt(II) and nickel(II) is studied with salicylidèneaniline (SAN). The phenol group in the Schiff base moiety leads to a large increase in the percentage of transition metal ions. SAN has both good reactivity towards metal ions and solubility in organic solvents. The solvent extraction of copper(II), cobalt(II) and nickel(II) with salicylidèneaniline from sulphate media is studied with the following parameters: pH, concentration of the extractant and the nature of diluent. The stoichiometry coefficients of the extracted species are determined by the slope analysis method. The extraction reaction proceeds by cation exchange mechanism and the extracted species are: CuL2HL, CoL2HL and NiL2. The extaction constants are evaluated for the different diluents. Under suitable conditions of pH, the solvent extraction of cobalt(II) and nickel(II) in different diluents leads to third phase formation. This tendency is confirmed from numerical extraction constants for both metal cations (log K ex = −15.10 ± 0.03 for nickel(II) in CHCl3) and (log K ex = −12.56 ± 0.04 for cobalt(II) in CHCl3). The extraction efficiency is found to follow the order Cu(II) > Co(II) > Ni(II).

Extraction of Co(II) by supported liquid membrane and solvent extraction using Cyanex 272 as an extractant: A comparison study

Cobalt has been extracted from dilute sulfate solution by supported liquid membrane (SLM) and solvent extraction (SX). The flux values in SLM process and distribution coefficients in SX have been compared. The microporous hydrophobic PVDF film has been used as the solid support for the liquid membrane. The Cyanex 272 has been used as extractant and mobile carrier in SX and SLM, respectively. Sulfuric acid was used as a stripping agent. In both the process effect of different parameters such as pH of feed solution, Cyanex 272 concentration, cobalt ion concentration in feed phase, strip acid concentration on cobalt flux J Co(II) and distribution coefficient D SX of cobalt has been investigated. Complete removal of cobalt from dilute sulphate solution at pH of 6.00, using 750 mol/m 3 of Cyanex 272 and strip acid concentration of 25 mol/m 3 has been achieved by SLM process. At the optimum condition of both the studies the flux value of 63.79 × 10 −6 mol/m 2 s. and distribution coefficient of 1136 has been achieved for SLM and SX process, respectively.

Simultaneous solvent extraction of cobalt and magnesium in the presence of nickel from sulfate solutions by Ionquest 801

AbstractThe simultaneous extraction of Co(II) and Mg(II) from nickel sulfate solutions has been carried out using the organophosphonic extractant Ionquest 801 diluted in Exxsol D‐80. Statistical design and analysis of experiments were used in order to determine the main effects and interactions of the solvent extraction parameters, which were the extraction pH at equilibrium, the temperature, the extractant concentration and the organic/aqueous phase ratio. A statistically designed experiment was also carried out to study the stripping of the Ionquest 801 organic phase loaded with cobalt and magnesium by sulfuric acid solution. The number of stages required for both extraction and stripping processes of cobalt and magnesium was evaluated. The results of continuous counter‐current mini‐plant tests demonstrated the simultaneous recovery of cobalt and magnesium from nickel sulfate solution. Copyright © 2005 Society of Chemical Industry

Simultaneous solvent extraction of cobalt and nickel in the presence of manganese and magnesium from sulfate solutions by Cyanex 301

The simultaneous extraction and separation of Co(II) and Ni(II) from manganese and mgnesium sulfate solutions have been carried out using the thio-organophosphinic extractant Cyanex 301, diluted in Exxsol D-80. Statistical design and analysis of experiments were used in order to determine the main effects and interactions of the solvent extraction factors, which were the extraction pH at equilibrium, temperature, extractant concentration and organic to aqueous phase ratio. A statistically designed experiment was also carried out in order to study the stripping of the cobalt- and nickel-loaded Cyanex 301 organic phase by hydrochloric acid solution. The Slope analysis method was used to determine the nature of the cobalt and nickel complexes extracted. The number of stages required for both extraction and stripping processes of cobalt and nickel was also evaluated. The results of the continuous counter current, mini plant tests demonstrated the simultaneous recovery of cobalt and nickel from manganese and magnesium sulfate solution.

Solvent Extraction of Cobalt and Nickel—The Chemistry and its Application*

The paper presents a review of the chemistry of solvent extraction of cobalt and nickel with reference to the application in the industry. The electronic configuration and the coordination chemistry of the cobalt and nickel ions provide fundamental basis relating to the extraction and separation.

Simultaneous determination of cobalt, copper, iron and vanadium in crude petroleum oils by HPLC

A method has been developed for the simultaneous formation and solvent extraction of cobalt (II), copper (II), iron (II) and vanadium (IV) complexes of bis (acetylpivalylmethane)ethylenediamine (H2APM2en) in methyl isobutyl ketone. The complexes are eluted from a reversed phase HPLC column with a mixture of methanol:water:acetonitrile and detection was at 260 nm. The method has been applied to the simultaneous determination of cobalt, copper, iron and vanadium in crude petroleum oils at the ng level.

Determination of Cobalt in Biological Samples by Inductively Coupled Plasma Atomic Emission Spectrometry After Preconcentration by Extraction With 1,5-bis(Di-2-Pyridylmethylene)thiocarbonhydrazide

Abstract A method is proposed for the solvent extraction of cobalt using 1,5-bis(di-2-pyridylmethylene) thiocarbonohydrazide (DPTH) as extractant. The optimum extraction conditions were evaluated from a critical study of the effect of pH. concentration of extractant, shaking time and ionic strength. The maximum volume ratio of the aqueous to organic phase was 30:1 for a single-stage extraction of 99-100 % of the metal ion. The detection limit is 0.9 ng/ml cobalt, and the calibration is linear from 0.9 to 1000 ng/ml. The effect of interferences was studied and no interferences from the elements commonly found in biological materials were observed. The extraction method was applied to the determination of cobalt in some biological materials using inductively coupled plasma atomic emission spectrometry (ICP-AES).

Liquid-liquid extraction of cobalt (II), nickel (II) and copper (II) from basic medium using some β-diketones

The solvent extraction of cobalt(II), nickel(II) and copper(II) using 2,4-pent-dione (Hacac) and 4-phenyl-2, 4-but-dione (Hbzac) is carried out by varying the reagent concentration and pH of the aqueous phase. Each of these metals is quantitatively separated (≈ 98%) from their binary mixtures with monovalent (Ag), divalent (Mn, Zn, Cd, Hg, Mg, Sn, Pb) and trivalent (Cr, Fe) metals. The extraction constants are calculated from the metal distribution data using linear regression analysis. The extracted species is MA2 in each case. A most significant result is separation of copper(II) from iron(III) which otherwise interferes when extracted from the acidic medium.

Effect of Changes in Structure of Phosphoric Acid Esters on Solvent Extraction of Cobalt (II) and Nickel (II)

Complexation behaviors of phosphoric acid esters with cobalt (II) and nickel (II) in solvent extraction have been assessed to elucidate the relationship between the structure of phosphoric acid esters and the extraction phenomena. By using phosphoric acid esters with aryl and alkyl groups, it is concluded that the structure of the organic groups in the phosphates plays an important role in the formation of the complexes and the extraction behaviors. In the case of di (nonylphenyl) phosphoric acid, the octahedral complexes of cobalt (II) and nickel (II) form in the extraction, and the compound extracts the metal ions at the lowest pH among the phosphates used. By changing the phenyl group with an alkyl group, the extraction curve shifts to higher pH, and the formation of the tetrahedral complex of cobalt increases in the extraction. Furthermore, the increase of the steric hindrance of the alkyl groups in the phosphates causes the shift of the extraction curves to higher pH. In addition, the selectivity of cobalt over nickel increases with increasing the steric hindrance of the phosphates.

Oxidation of Cobalt(II) during Its Solvent Extraction with Acetylacetone

During the solvent extraction of cobalt(II) with acetylacetone, benzoylacetone, dibenzoylmethane, and benzoyl-trifluoroacetone in toluene, oxidation of the metal ion was found only with acetylacetone. The oxidation was assumed to be caused by dissolved atmospheric oxygen in the organic solvent. The rate of oxidation was first order with respect to the acetylacetone concentration, and was nearly the same when the diluent was carbon tetrachloride. This oxidation was slowed down by the addition of trioctylphosphine oxide. The shape of the extraction curve of cobalt(II) with acetylacetone as a function of the hydrogen-ion concentration was different when the time for the two-phase agitation was one hour, one day, and one week. The reason for this is discussed from the standpoint of the slow oxidation of cobalt(II) and of the acetylacetone concentration in the organic phase.

Synergistic solvent extraction of cobalt(III) by acetylacetone mixed with alcohol, ketone, ether and tributyl phosphate from acetate buffer solutions

The extraction of Co(III) has been studied from acetate medium by acetylacetone in CHCl3. The effect of adding different synergetic bases (S) like diisobutyl ketone, dibutyl ether, diisobutyl carbinol and tributyl phosphate was studied. The extracted species is Co(OH)2 (AcAc)·2HAcAc by acetylacetone only while the species formed for the mixed extractants are Co(OH)2 (AcAc)·(HAcAc) (S)n where “n”=1 or 2. The corresponding thermodynamic parameters were determined and discussed.

The kinetics of the solvent extraction of cobalt (II) and lead (II) with versatic acid

In the solvent extraction of cobalt (II) and lead (II) from aqueous ammonium nitrate solutions with Versatic 10 in hexane, initial extraction rates were measured at 303 K using a Lewis-type stirred transfer cell. In the extraction of cobalt(II), the initial extraction rate expression was found to be described by N = κ 1 C AW/[H +] in the high concentration region of Versatic 10 and by N = κ II C AW C BO 2/[H +] 2 in the low concentration region of Versatic 10. An interfacial reaction mechanism was proposed in order to give a reasonable interpretation of the observed rate expressions. In the extraction of lead(II), the initial extraction rate at low pH was found to be described also by the second rate expression shown above. At high pH, the rate is independent of hydrogen ion concentration. From this result, it was presumed that only the non-hydrated aquo-cation of lead(II) takes part in complex formation at the interface.

β‐ジケトンとテトラブチルアンモニウムイオンによるコバルト（ＩＩ）三元錯体の溶媒抽出に及ぼす配位子の性質の影響

1mol/dm3の塩化ナトリウム水溶液中のコバルト(II)を, 5種類のβ-ジケトン(HA)で四塩化炭素中に溶媒抽出するさいに, 水相にテトラブチルアンモニウムイオン(TBA+)を添加したところ, アセチルアセトンとベンゾイルアセトンによる抽出に対しては影響がみられなかったが, トリフルオロアセチルアセトンとベンゾイルトリフルオロアセトンでは抽出が増大し, ヘキサフルオロアセチルアセトンでは, さらに大きな抽出の増大がみられた。実験データを解析して系内の化学平衡をもとめたところ, これらの抽出の増加はいずれも無荷電錯体, CoA2のほかに三元錯体CoA3-TBA+の抽出が起こるためであることが結論された。このような結果に基づいて,β-ジケトンの性質と三元錯体の安定度あるいは抽出の増大との関係が考察された。

ANAEROBIC EXTRACTION OF COBALT IN A PULSE COLUMN

ABSTRACT The effects of excluding air (oxygen) from a cobalt solvent extraction circuit were studied for LIX 64N extractant. After solvent extraction of divalent cobalt from ammoniacal solutions with chelating extractants such as LIX 64N, the loaded Co-chelate is believed to oxidize to a stable trivalent complex which resists subsequent stripping with mineral acids. To Improve stripping efficiency, cobalt was extracted and stripped in the absence of oxygen in pulsed, perforated-plate columns that were designed and constructed by the Bureau of Mines. When the ammoniacal cobalt(II) sulfate and LIX 64N solutions were purged, blanketed, and pulsed with argon, cobalt extraction exceeded 99%, and stripping with 1 vol % H2SO2 reached 98.5%. The stripped extractant was recycled to the extraction column with no loss of extraction efficiency in six passes through the circuit.

Solvent extraction of cobalt and nickel with 5,7-dichloro-2-methyl-8-hydroxyquinoline into chloroform

The distribution equilibria of the cobalt and nickel complexes with 5,7-dichloro-2-methyl-8-hydroxyquinoline in the water-chloroform system have been studied. The influence of pH, reagent and metal concentrations, and the presence of NaClO4 or Na2SO4 in the aqueous phase has been studied. From slope analysis of the distribution curves the compositions of the extracted species have been determined. The cobalt complexes extracted are [Co2R3(RH)]ClO4, [Co2R3(RH)3]ClO4 and Co2R4; in all of them the metal is in oxidation state Co(II). For nickel the NiR2 and NiR2(RH) complexes are extracted.

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 Cobalt From Nickel in Sulfate Leach Liquors

In 1978, Anschutz Mining Corp. began efforts to develop the Madison Cobalt Project in southeast Missouri. Preliminary metallurgical studies indicated that intermediate grade cobalt products, suitable for shipment to existing refineries, could be recovered from the sulfide mineralization of the ore body. However, tolling and freight charges were significant, as the refineries were located outside the US. These refineries would not satisfy the goal of strategically insulated production of superalloy-grade cobalt. The acquisition of proven, readily available refinery technologies was then evaluated. However, licensing costs were substantial and the “proven” technologies were not directly applicable to the unique chemistry of Madison materials. Faced with these challenges, Anschutz, in conjunction with the Colorado School of Mines Research Institute, embarked on an effort to develop a sulfate-based separation and refining process. CSMRI performed bench-scale and continuous pilot experiments on solutions generated through other pilot campaigns conducted by Lurgi, Hazen Research, and Sherritt-Gordon. The results indicated that cobalt could be selectively extracted from sulfate media using a new generation of organophosphates. The solvent extraction system produced a solution suitable for electrolysis of high-purity cobalt. Preliminary cost studies indicated the novel process was competitive with other refinery systems. Plans to develop the detailed engineering-design information required to commercialize the process were abandoned when the price of cobalt collapsed to less than $17.64/kg ($8.00 per lb).

Solvent Extraction of Cobalt(ll) and Nickel(ll) by a Quaternary Ammonium Thiocyanate

Abstract The solvent extraction of cobalt(II) and nickel(II) into xylene solutions of a quaternary ammonium thiocyanate (R4N.NCS) has been investigated and shown to depend markedly upon the identity of the counteranion (X−) present in the aqueous phase. The extent of extraction of both metals increases with increasing stability of the corresponding ion-pair, R4N.X. The dependence of metal distribution upon the concentrations of R4N.NCS, R4N.X, and X− is consistent with the extraction of cobalt from sulfate (X− = 1/2SO4 2), chloride (X− = Cl−), bromide (X− = Br−), and nitrate (X− = NO3 −) media according to the stoichiometry The importance of certain deviations from ideal behavior, namely association of the extractant in the organic phase and CoSO4 ion-pair formation in the aqueous phase, has been demonstrated. Examination of the electronic spectra of the organic extracts reveals that cobalt is extracted as the tetrahedral anion Co(NCS)4 2- while nickel forms an octahedral complex, probably Ni(NCS)4(H2O)2 ...