Hydrophobic ionic liquids as novel extractants for gold(I) recovery from alkaline cyanide solutions

Yang, Xiangjun; Yang, Ruisi; Shi, Deqiang; Wang, Shixiong; Chen, Jing; Guo, Hong

doi:10.1002/jctb.4418

Cited by 38 publications

(25 citation statements)

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“…[1,9] They have consequently been considered for a variety of applications such as separation technology, [10,11] catalysis, [12][13][14] biomass treatment [15,16] and energy storage. [1,9,17,18] For industrial applications of IL as alternative green solvents, the determination of both decomposition and melting temperatures is of paramount importance.…”

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confidence: 99%

Thermal stability of imidazolium-based ionic liquids

et al. 2016

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confidence: 99%

Thermal stability of imidazolium-based ionic liquids

et al. 2016

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“…17 Ionic liquids have been used to study the electrochemical dissolution/deposition of gold as a method for avoiding the use of cyanide. [21][22][23] In addition Qin et al have studied the immersion deposition of gold from tetrachloridoauric acid in the ionic liquid butylmethylimidazolium hexafluorophosphate onto zinc substrate. 24 Wang et al showed that uniform and bright ENIG coatings could be obtained from a solution of 500 g L -1 choline chloride in water adjusted to pH 2 with HCl and 1 g L -1 tetrachloridoauric acid.…”

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confidence: 99%

Electrochemistry and speciation of Au⁺in a deep eutectic solvent: growth and morphology of galvanic immersion coatings

Ballantyne

Forrest

Frisch

et al. 2015

Phys. Chem. Chem. Phys.

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In this study we compare the electrochemical and structural properties of three gold salts AuCl, AuCN and KAu(CN)2 in a Deep Eutectic Solvent (DES) electrolyte (Ethaline 200) in order to elucidate factors affecting the galvanic deposition of gold coatings on nickel substrates. A chemically reversible diffusion limited response was observed for AuCl, whereas AuCN and KAu(CN)2 showed much more complicated, kinetically limited responses. Galvanic exchange reactions were performed on nickel substrates from DES solutions of the three gold salts; the AuCN gave a bright gold coating, the KAu(CN)2 solution give a visibly thin coating, whilst the coating from AuCl was dull, friable and poorly adhesive. This behaviour was rationalised by the differing speciation for each of these compounds, as evidenced by EXAFS methods. Analysis of EXAFS data shows that AuCl forms the chlorido-complex [AuCl2] − , AuCN forms a mixed [AuCl(CN)] − species, whereas KAu(CN)2 maintains its [Au(CN)2] − structure. The more labile Cl − enables easier reduction of Au when compared to the tightly bound cyanide species, hence leading to slower kinetics of deposition and differing electrochemical behaviour. We conclude that metal speciation in DESs is a function of the initial metal salt and that this has a strong influence on the mechanism and rate of growth, as well as on the morphology of the metal deposit obtained. In addition, these coatings are also extremely promising from a technological perspective as Electroless Nickel Immersion Gold (ENIG) finishes in the printed circuit board (PCB) industry, where the elimination of acid in gold plating formulation could potentially lead to more reliable coatings. Consequently, these results are both significant and timely. IntroductionGold plating processes are widely used in the materials finishing, decorative and electronics industries due to their high reliability, electrical conductivity and corrosion resistance. 1 The key characteristic feature of these noble metal coatings is the lack of insulating surface oxides. 2 Electrolytic, 3 electroless, 4 and immersion plating 5 are the three common electrochemical methods used for the coating of conducting substrates with gold films. In each of these processes the conventional/commercial plating bath chemistry is dominated by the choice of the dicyanidoaurate anion [Au(CN) 2 ] − as the gold source 6 due to its high stability 7 and the ability to yield fine grained deposits. 8 In electroplating experiments, acidic plating baths around pH 5 are used to produce soft gold coatings, whilst alkaline and neutral baths are used to produce hard gold. 8 However, there are significant safety concerns, as well as issues regarding the disposal of waste, where cyanide based processes are present. In addition, the requirement of large negative reduction potentials can also lead to the coreduction of hydrogen ions. 9 As such, there have been cyanide free gold plating solutions developed, primarily based upon sulphite and thiosulfate complexes, however these are limited to...

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“…aqueous two phase systems (ATPs), leached using aqueous alkaline cyanide (AAC), cloud point extraction (CPE), liquid-liquid microextraction, microemulsion extraction, and ion exchange extraction [65][66][67][68][69] . IL extraction is a potential alternative method to separate gold from mixture of metal ions.…”

Section: Performance and Modified Of Ionic Liquids Extraction In Goldmentioning

confidence: 99%

“…IL extraction is a potential alternative method to separate gold from mixture of metal ions. As an example, (1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM][PF6])) is known has potential to increase solubility of metal include Au nanoparticles 65,70 . ILATPs have made interest pay attention for some recent researchers to separate gold in industrial scale since currently to recover gold from secondary source acid leaching or organic solvent extraction is still used.…”

Section: Performance and Modified Of Ionic Liquids Extraction In Goldmentioning

confidence: 99%

“…Their research showed that the IL has good performance to recover gold is about 98%. Moreover, Yang and coworkers 65 have been separated gold used [C8MIM][PF6] from gold leached using aqueous alkaline cyanide with recovery of 98 %. Based on several researches, it is shown that IL has good properties to increase the performance of gold separation.…”

Section: Performance and Modified Of Ionic Liquids Extraction In Goldmentioning

confidence: 99%

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Solvent extraction of gold using ionic liquid based process

Makertihartha

Zunita

Rizki

et al. 2017

AIP Conference Proceedings

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Abstract. In decades, many research and mineral processing industries are using solvent extraction technology for metal ions separation. Solvent extraction technique has been used for the purification of precious metals such as Au and Pd, and base metals such as Cu, Zn and Cd. This process uses organic compounds as solvent. Organic solvents have some undesired properties i.e. toxic, volatile, excessive used, flammable, difficult to recycle, low reusability, low Au recovery, together with the problems related to the disposal of spent extractants and diluents, even the costs associated with these processes are relatively expensive. Therefore, a lot of research have boosted into the development of safe and environmentally friendly process for Au separation. Ionic liquids (ILs) are the potential alternative for gold extraction because they possess several desirable properties, such as a the ability to expanse temperature process up to 300°C, good solvent properties for a wide range of metal ions, high selectivity, low vapor pressures, stability up to 200°C, easy preparation, environmentally friendly (commonly called as "green solvent"), and relatively low cost. This review paper is focused in investigate of some ILs that have the potentials as solvent in extraction of Au from mineral/metal alloy at various conditions (pH, temperature, and pressure). Performances of ILs extraction of Au are studied in depth, i.e. structural relationship of ILs with capability to separate Au from metal ions aggregate. Optimal extraction conditon in order to gain high percent of Au in mineral processing is also investigated.

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Hydrophobic ionic liquids as novel extractants for gold(I) recovery from alkaline cyanide solutions

Cited by 38 publications

References 43 publications

Thermal stability of imidazolium-based ionic liquids

Thermal stability of imidazolium-based ionic liquids

Electrochemistry and speciation of Au⁺in a deep eutectic solvent: growth and morphology of galvanic immersion coatings

Solvent extraction of gold using ionic liquid based process

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Hydrophobic ionic liquids as novel extractants for gold(I) recovery from alkaline cyanide solutions

Cited by 38 publications

References 43 publications

Thermal stability of imidazolium-based ionic liquids

Thermal stability of imidazolium-based ionic liquids

Electrochemistry and speciation of Au+in a deep eutectic solvent: growth and morphology of galvanic immersion coatings

Solvent extraction of gold using ionic liquid based process

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Electrochemistry and speciation of Au⁺in a deep eutectic solvent: growth and morphology of galvanic immersion coatings