Alpha-substituted oxime extractants—I Extraction of Cu(II), Ni(II), Co(II) and Fe(III) by aliphatic alpha-hydroxyoximes

doi:10.1016/0022-1902(75)80475-1

Journal of Inorganic and Nuclear Chemistry

Volume 37, Issue 5, May 1975, Pages 1235-1242

https://doi.org/10.1016/0022-1902(75)80475-1 Get rights and content

Abstract

Several aliphatic α-hydroxyoximes (H₂A) not previously characterized are described. The extractability by solutions of these reagents in toluene from 1 M (Na, NH₄)NO₃ media decreases in the order Fe(III) > Cu(II) > Co(II) ∼ Ni(II). Copper complexes of the types Cu(HA)₂ and CuA are formed, the latter being polymeric in the organic phase. The nickel(II) and iron(III) complexes have the compositions Ni(HA)₂ and Fe(HA)₃ respectively. Extraction of cobalt(II) proceeds irreversibly; cobalt(III) is not extracted. The order of pH values at which different α-hydroxyoximes extract a given metal parallels the expected order of steric hindrance offered by the substituent alkyl groups to the formation of the metal complex.

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Selective solvent extraction of nickel and cobalt from a Ni lateritic sulfuric solution using synergism caused by LIX860N-IC and Versatic 10
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This work investigated the efficiency of the LIX860N-IC + Versatic 10 synergistic system (pH range 2–6, 40 °C) to treat an aqueous sulphate solution containing Ca, Co, Cu, Mg, Mn, Ni, and Zn, which mimics a liquor obtained by the sulfation-roasting-leaching process applied to a lateritic Brazilian Ni ore, after precipitation of Fe, Al, and Cr. Almost complete extraction of Cu was observed at pH 2 (1 stage, A/O = 1:1), while a rise in the selectivity of Ni/(Mn + Zn) and Co/(Mn + Zn) was identified at pH 2–6 and pH > 5, respectively. By varying both extractant concentrations, an organic phase containing 0.4 M LIX860N-IC + 0.4 M Versatic 10 was selected to obtain high Ni and Co extractions with low Mn and Zn extractions. At the studied pH range, antagonism occurred for Ca, Cu, and Mg extractions, while synergism was found for Ni and Zn extractions. For Co and Mn, such an effect was pH dependent: antagonism at pH 2–5 and below 4.5, respectively, otherwise synergism was identified. The stoichiometry of Co and Ni extractions with the LIX860N-IC + Versatic 10 system were obtained by data fitting supported by statistical analysis. Ni and Co were complete and selectively extracted together (>99.9 %) at pH 4.5 (2 stages, A/O = 1:1.1) with low extractions of Mn (3.3 %) and Zn (20 %), leaving Ca and Mg in the raffinate. In the sequence, while Zn was completely scrubbed off from the loaded organic using a scrub solution containing 3.5 g/L Ni and 0.2 g/L Co at pH 4.5 (1 stage, O/A ≤ 15), Mn scrubbing efficiency achieved from 85.6 % to 97.8 % at an O/A ratio ranging from 5 to 25, which can be attributed to possible Mn oxidation in the extract. Finally, Ni was completely stripped out (3 stages, A/O = 10:1), using a synthetic Ni spent electrolyte (50 g/L Ni + 1 M H₂SO₄), while Co stripping increased from 70 % in the first stage to 75.4 % in the second, and to only 76 % in the third stage, indicating that Co oxidation might have occurred in the loaded organic solution. The remaining Co in the extract was stripped out with 5 M HCl (2 stages, A/O = 1:1). Consequently, to avoid Mn and Co oxidations in the loaded organic solution, the solvent extraction circuit with LIX860N-IC + Versatic 10 requires an operation under an inert atmosphere.
Identification and regeneration of degradation products from phenolic hydroxyoxime-based extractant in long-term copper solvent extraction plant
2019, Hydrometallurgy
Citation Excerpt :
Hydroxyoxime derivatives are known as excellent selective extractants for the recovery of various metal ions, such as in nickel separation from ammoniacal media (Rice et al. 1978), nickel, cobalt, iron and copper separation from nitrates media (Preston 1975; Burkin and Preston, 1975), nickel and cobalt separation from manganese, calcium and magnesium (Cheng 2006), nickel and cobalt separation from acidic aqueous solutions (Zhang et al. 2001), copper separation from acidic wastewater (Zhang et al. 2010), as well as copper and nickel from ammoniacal solutions (Duan et al., 2017; Inoue and Tsunomachi, 1984; Yang et al. 2016).
The phenolic hydroxyoxime-based extractant has been discovered to degrade gradually in commercial copper solvent extraction plant. The main degradation products occurred through hydrolysis rather than oxidation or Beckmann rearrangement, which were identified as 1-(2-hydroxy-5-nonylphenyl)propan-1-one and 5-nonyl salicylaldehyde through instrumental analysis. The degradation products could reduce the extraction isotherm, the stripping isotherm and the transfer of copper. Moreover, the extractant regeneration of 5-nonyl salicylaldoxime from 5-nonyl salicylaldehyde was achieved with hydroxylamine sulfate. It was observed that the copper loading capacity of regenerated extractant increased by 64%, compared to the copper loading of untreated hydroxyoxime extractant.
Mechanism of poisoning hydroxyoximes by cobalt in different organic systems
2018, Hydrometallurgy
Citation Excerpt :
Increased attention has been paid to determining the cause of the poisoning and finding a possible solution. It is generally accepted that a chelating/oxidation reaction occurs in cobalt-loaded organic solutions, resulting in the formation of a very stable Co3+-hydroxyoxime chelate complex in the presence of oxygen (Preston, 1975; Burkin, 1975). This complex is much more stable than the Co2+-hydroxyoxime complex and is difficult to dissociate, unless Co3+ is reduced to the Co2+ via the addition of reducing reagents such as zinc and iron powders into the organic solution (Groves and Redden, 1990; Mackenzie et al., 2006).
Poisoning of 2-hydroxy-5-nonylbenzaldoxime (Mextral 84H) by cobalt in the presence of neodecanoic acid (Versatic 10) and bis(2-ethylhexyl) phosphoric acid (P204) diluted in aliphatics was comparatively studied. The cobalt-organic extractants species structure and stoichiometry were determined by slope analysis, Fourier transform infrared (FT-IR) spectrometer, visible absorption and cyclic voltammetry. It is found that P204 can significantly inhibit the poisoning of Mextral 84H by cobalt and the poisoning is weakened with the increase of P204 concentration while Versatic 10 has no effect on it. The stoichiometries of adducts formed in the organic phase with Mextral 84H (HL) in the presence of Versatic 10 and P204 (HA) are CoL₂ · 2H₂O and Co(H₂A₂L₂), respectively. The divalent cobalt in the CoL₂ · 2H₂O complex is easily oxidized to trivalent cobalt because of its inner-orbital d²sp³ hybridization, resulting in low oxidation potential and the poisoning of Mextral 84H by cobalt in the presence of oxygen. With the addition of P204, the hybridization configuration of the cobalt complex transforms from d²sp³ to the more stable sp³d², and the oxidation potential of divalent cobalt in the organic phase significantly increases to prevent the Co(H₂A₂L₂) complex from being oxidized, resulting in the significantly inhabitation of the poisoning Mextral 84H by cobalt in the presence of oxygen.
LIX<sup>®</sup>63 stability in the presence of Versatic 10 under proposed commercial extract and strip conditions, part III: Effect of manganese and cobalt loading on oxime stability at 30 °c
2010, Hydrometallurgy
Citation Excerpt :
This darkening has previously been suspected to be attributable to irreversible metal complexation (Barnard and Turner, 2008b). Cobalt has been known to irreversibly complex with this oxime when on its own (Preston, 1975), although the presence of an organic carboxylic acid such as in the current system appeared to overcome that process (Cheng, 2006). To test the possibility of irreversible cobalt loading accounting for the ‘missing’ cobalt, the final organic samples (10 mL) were reductively stripped by stirring with excess zinc metal (0.32 g) and 100 g/L sulfuric acid (10 mL) at room temperature for 20 min.
The combination of LIX^®63 with the carboxylic acid Versatic 10 exhibits synergistic properties, enabling direct separation of Co and Zn from Mn, Mg and Ca, a process of interest to the proposed El Boleo copper/cobalt project. Previous work on the chemical stability of this system had revealed the potential for rapid degradation of LIX^®63 oxime (‘oxime’) at high temperature (40, 50 °C) when extracting cobalt and zinc from El Boleo solutions. The present study under extract conditions at 30 °C found increased manganese loading, achieved by increasing operating pH from 4.5 to 6.0, facilitated increased rates of oxime degradation and ‘irreversible’ loading of cobalt. This cobalt was able to be reductively stripped using zinc metal, yielding anti oxime and ‘keto-oxime’. Operation at pH 4.5 resulted in low manganese loading (about 0.2 g/L) and a calculated oxime half life of 67 weeks. Increasing the pH to 6.0 resulted in manganese loading of 2.5 g/L and a decrease in oxime half life to 24 weeks. Operation at pH 6.0 in the absence of manganese gave an oxime half life of 66 weeks. Zinc loading, cobalt loading and changes in pH between 4.5 and 6.0 (excluding the resulting impact on manganese loading) did not appear to have any adverse effect on oxime stability. At a given pH (5.0), ‘irreversible’ Co loading increased with increasing Co concentration in the aqueous solution. This did not have any noticeable effect on oxime half life.
The metal:oxime:carboxylic acid stoichiometries of the Zn, Mn and Co synergist complexes were determined by continuous variation and maximum loading studies to be 1:3:2 for all three metals although 1:2:2 remained a possibility for manganese.
Inter-conversion of syn oxime to anti oxime was observed to occur via two different mechanisms under the conditions used: a rapid process facilitated by manganese complexation; and a slower, temperature-based isomer re-equilibration process which occurred in the absence of manganese. This inter-conversion process, which resulted in increased manganese and zinc loading occurring relative to fresh organic (cobalt already being fully loaded), also opens up the possibility of decreasing the amount of LIX^®63 required in the El Boleo process.
Recovery of nickel and cobalt from laterite leach solutions using direct solvent extraction: Part 1 - Selection of a synergistic SX system
2010, Hydrometallurgy
The separation of nickel and cobalt from impurities such as manganese, magnesium and calcium using solvent extraction with Versatic 10 was largely improved by the addition of a synergistic reagent LIX63 (an α-hydroxyoxime) or 4PC (a pyridine carboxylate ester). With the organic systems containing Versatic 10 alone, the separation factors of nickel and cobalt over manganese were 6 and 15 respectively. When 4PC was added to the system, these increased to 147 and 1870 respectively, and with LIX63, they were even higher at 534 and 7720 respectively. This indicates that the synergistic solvent extraction (SSX) system with Versatic 10 and LIX63 performed very well and better than that with Versatic 10 and 4PC.
The SSX system consisting of 0.5 M Versatic 10, 0.45 M LIX63 and 1.0 M TBP in Shellsol D70 performed the best among the systems tested containing LIX63. After a single contact, the extraction of Ni and Co was 99.6% and 96.9%, respectively. Only 6 mg/L Mn, 8 mg/L Mg and 1 mg/L Ca were found in the loaded organic solution. The manganese scrub efficiency was 97.7% at pH 5.3, resulting in a scrubbed organic solution containing only 0.8 mg/L Mn. Over 99% nickel, cobalt and manganese were stripped at pH 2.0, indicating easy stripping of these metals.
The SSX system consisting of 0.5 M Versatic 10 and 1.0 M 4PC in Shellsol D70 performed the best among the systems tested containing 4PC. After a single contact, the extraction of Ni and Co was 99.4% and 89.4%, respectively. Some 200 mg/L Mn, 10 mg/L Mg and 48 mg/L Ca were found in the loaded organic solution. The manganese could not be scrubbed at the tested pH range of 5.4–6.0. Very fast Ni and fast Co stripping kinetics were observed, however, the Mn stripping kinetics were very slow. After 2 min of stripping, only 1.22% Mn was stripped.
It is concluded that the SSX system containing 0.5 M Versatic 10, 0.45 M LIX63 and 1.0 M TBP performed much better than the SSX system containing 0.5 M Versatic 10 and 1.0 M 4PC in terms of both manganese and calcium behaviour in extraction, scrubbing and stripping.
Extraction of Co(II) and Ni(II) from concentrated HCl solutions using Alamine 336
2009, Hydrometallurgy
Extraction of Co(II) and Ni(II) from aqueous HCl solutions into organic Alamine 336–m-xylene systems were studied. Extraction experiments were repeated for three initial metal concentration ratios with total initial metal concentration of 7 g L^− 1, each at 1, 5 and 10 M HCl. The extraction percentage, E, in terms of volume percentage of Alamine content, V_e, in solvent mixture, were determined for each metal. Optimal Alamine 336 contents were reported for a single stage extraction. The amine loading factor and separation factor values were also determined in terms of V_e. Alamine 336 was found to be a suitable extracting and separating agent for Co(II)–Ni(II) containing solutions at 5 M HCl.

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Alpha-substituted oxime extractants—I Extraction of Cu(II), Ni(II), Co(II) and Fe(III) by aliphatic alpha-hydroxyoximes

Abstract

Talanta

Analyt. Chim. Acta

Ber. dt. chem. Ger.

Ind. Eng. Chem. Analyt.

J. Indian chem. Soc.

Chem. Obzor