Metal Complexes for Hydrometallurgy and Extraction

Tasker, Peter A.; Plieger, Paul G.; West, Lee C.

doi:10.1016/b0-08-043748-6/09011-3

Cited by 58 publications

(82 citation statements)

References 246 publications

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“…Despite simple b-diketones having been used as extractants in numerous liquid-liquid extraction studies (including, for example, for mineral processing applications 27 there appears to be no report of the use of bis-b-diketone ligands of type H 2 L 1 in a similar role even though individual examples of the latter have been known for a considerable time 28 and are readily synthesised in high yield from relatively inexpensive precursors.…”

Section: Liquid-liquid Extraction Studiesmentioning

confidence: 99%

Neutral (bis-β-diketonato) iron(iii), cobalt(ii), nickel(ii), copper(ii) and zinc(ii) metallocycles: structural, electrochemical and solvent extraction studies

et al. 2007

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Neutral dimeric metallocyclic complexes of type [M 2 (L 1 ) 2 B n ] (where M = cobalt(II), nickel(II) and zinc(II), L 1 is the doubly deprotonated form of a 1,3-aryl linked bis-b-diketone ligand of type 1,3-bis(RC(O)CH 2 C(O))C 6 H 4 (R = Me, n-Pr, t-Bu) and B is pyridine (Py) or 4-ethylpyridine (EtPy)) have been synthesised, adding to similar complexes already reported for copper(II). New lipophilic ligand derivatives with R = octyl or nonyl were also prepared for use in solvent extraction experiments. Structural, electrochemical and solvent extraction investigations of selected metal complex systems from the above series are reported, with the X-ray ] has been examined. Oxidative processes for the complexes are dominantly irreversible, but several examples of quasireversible behaviour were observed and support the assignment of an anodic process, seen between +1.0 and +1.6 V, as a metal-centred oxidation. The reduction processes for the respective metal complexes are not simple, and irreversible in most cases. Solvent extraction studies (water/chloroform) involving variable concentrations of metal, bis-b-diketone and heterocyclic base have been performed for cobalt(II) and zinc(II) using a radiotracer technique to probe the stoichiometries of the extracted species in each case. Synergism was observed when 4-ethylpyridine was added to the bis-b-diketone ligand in the chloroform phase. Competitive extraction studies show a clear uptake preference for copper(II) over cobalt(II), nickel(II), zinc(II) and cadmium(II).

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Section: Liquid-liquid Extraction Studiesmentioning

confidence: 99%

Neutral (bis-β-diketonato) iron(iii), cobalt(ii), nickel(ii), copper(ii) and zinc(ii) metallocycles: structural, electrochemical and solvent extraction studies

et al. 2007

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“…In particular, we avoided the use of toxic reagents or strong acid in high concentrations, particularly those which produce toxic fumes such as concentrated H 2 SO 4 or HNO 3 , commonly used for copper and base metals leaching [2][3][4]. 1 In the case of reaction (A), the diiodine Me 2 dazdt·2I 2 adduct can be used in place of the mixture of the two reagents.…”

Section: Details On the Gold Leaching Reactionmentioning

confidence: 99%

“…A variety of hydrometallurgical procedures has been proposed in the past by several authors for the dissolution/extraction of Noble-Metals (NMs) [2][3][4]. The most significant approaches are generally based on the following two processes: (1) cyanidation based on the use of cyanide salts into basic media with subsequent adsorption on activated carbon and reduction of the complex by electro-winning.…”

Section: Introductionmentioning

confidence: 99%

From trash to resource: a green approach to noble-metals dissolution and recovery

Serpe

Artizzu²,

Espa³

et al. 2014

Green Processing and Synthesis

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Abstract:A process based on the lixiviant properties of organic mixtures of dihalogen/S,S-ligands, N,N′-dimethylperhydrodiazepine-2,3-dithione (Me 2 dazdt) and tetraalkylthiuramdisulphide (Et 4 TDS) in the presence of diiodine, for gold recovery from the non-ferrous metal fraction of real shredded waste electric and electronic equipment (WEEE), is presented here. Selective dissolution of metals is achieved through a sequence of three steps where the oxidation of different kinds of metals is achieved by using: (1) refluxing water solutions of HCl 1:5 under Ar atmosphere (Sn, Zn, etc.); (2) water solutions of NH 3 /(NH 4 ) 2 SO 4 mixtures in the presence of H 2 O 2 on the resting sample (Cu, Ag); and (3) acetone solutions of Me 2 dazdt or Et 4 TDS/ I 2 mixtures on the final residue (Au). Each step is followed by a further treatment for: (1) metal recovery, in the case of Au, Cu, Ag; and (2) inertization, in the case of heavy metals. As a whole, the process is very promising for effective recovery of gold and other valuable noble-metals and for using non harmful reagents in mild conditions.

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“…[1,2] The latter rely upon control of partition coefficients and solubilities such that anion exchange can be used to transfer the chlorometallate to a water-immiscible solvent in a pH-dependent equilibrium [Eq. (1)].…”

mentioning

confidence: 99%

Outer‐Sphere Coordination Chemistry: Selective Extraction and Transport of the [PtCl₆]²⁻ Anion

Bell¹,

Westra²,

Warr³

et al. 2008

Angew Chem Int Ed

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What's on the outside? Selective extraction and transport of [PtCl6]2− from aqueous acidic solutions in the presence of excess chloride has been demonstrated through outer‐sphere coordination of the metalloanion by tripodal polyamide and polyurea receptors (see picture; Pt purple, N blue, O red, Cl green). Loading and stripping of the organic phase can be controlled by variation of the pH value of the aqueous solution.

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Metal Complexes for Hydrometallurgy and Extraction

Cited by 58 publications

References 246 publications

Neutral (bis-β-diketonato) iron(iii), cobalt(ii), nickel(ii), copper(ii) and zinc(ii) metallocycles: structural, electrochemical and solvent extraction studies

Neutral (bis-β-diketonato) iron(iii), cobalt(ii), nickel(ii), copper(ii) and zinc(ii) metallocycles: structural, electrochemical and solvent extraction studies

From trash to resource: a green approach to noble-metals dissolution and recovery

Outer‐Sphere Coordination Chemistry: Selective Extraction and Transport of the [PtCl₆]²⁻ Anion

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Metal Complexes for Hydrometallurgy and Extraction

Cited by 58 publications

References 246 publications

Neutral (bis-β-diketonato) iron(iii), cobalt(ii), nickel(ii), copper(ii) and zinc(ii) metallocycles: structural, electrochemical and solvent extraction studies

Neutral (bis-β-diketonato) iron(iii), cobalt(ii), nickel(ii), copper(ii) and zinc(ii) metallocycles: structural, electrochemical and solvent extraction studies

From trash to resource: a green approach to noble-metals dissolution and recovery

Outer‐Sphere Coordination Chemistry: Selective Extraction and Transport of the [PtCl6]2− Anion

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Product

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Outer‐Sphere Coordination Chemistry: Selective Extraction and Transport of the [PtCl₆]²⁻ Anion