Anodic behaviour of gold in cyanide solution

Pan, Ting; Wan, Chi‐Chao

doi:10.1007/bf00610956

Cited by 25 publications

(10 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The gold dissolution behavior in conventional cyanidation was observed by CV (cyclic voltammetry) and the result was shown in Figure 2. The shape and feature parameters of the oxidized part in the curve were consistent with the finding of Kudry and Jiang Tao [16][17][18]. The anodic dissolution of gold plate appears three oxidative peaks within the potential range of −0.6 to 0.8 V, indicating that the gold plate in cyanide leaching has undergone three different oxidative dissolutions.…”

Section: Gold Dissolution Behavior By Cyclic Voltammetrysupporting

confidence: 86%

Study on Intensification Behavior of Bismuth Ions on Gold Cyanide Leaching

Yang

Lai

Zhong

et al. 2019

Metals

View full text Add to dashboard Cite

Gold cyanide leaching is inefficient with conventional cyanidation. Bismuth ions can improve the efficiency of gold cyanidation by intensifying gold dissolution. The electrochemical behavior, structure information, and surface product of gold anodic dissolution were studied during the intensification of bismuth ions on gold cyanide leaching. The electrochemical analysis showed that the bismuth ions can not only improve anode current density, but also make gold dissolve at a lower potential, increase the corrosion current and intensify gold anodic dissolution. The microstructure analysis showed that bismuth ions intensified the cyanide corrosion of the gold surface, causing a large number of loose honeycombs, gullies, pits, and large holes on the gold surface. The XPS, FT-IR, and Raman analysis showed that there is weak information of C≡N in the spectrum of Bi intensification contrasting to that of conventional cyanidation. Cyanide compounds may be the insoluble AuCNads, which does not deposit on the surface of gold plate after Bi intensification cyanidation. The insoluble intermediate AuCNads is likely to react promptly with CN- to form soluble Au(CN ) 2 − , making less insoluble AuCNads deposits on the gold surface. Therefore, bismuth ions can promote the dissolution of insoluble AuCNads, prevents its passivation film to cover around the gold plate, keeps cyanide good contact with gold, and finally accelerates the cyanide dissolution of gold.

show abstract

Section: Gold Dissolution Behavior By Cyclic Voltammetrysupporting

confidence: 86%

Study on Intensification Behavior of Bismuth Ions on Gold Cyanide Leaching

Yang

Lai

Zhong

et al. 2019

Metals

View full text Add to dashboard Cite

show abstract

“…Au͑III͒ species has been reported to loosely attach to the gold surface, allowing cyanide ions to penetrate and participate in Reactions 1-3, as gold hydroxide complex. 17,26,27 When abundant CN − and Au͑CN͒ 2 −1 are both present, the oxidation path follows a similar path.…”

Section: Resultsmentioning

confidence: 80%

“…A three-step oxidation mechanism for gold in the presence of cyanide has been proposed [15][16][17][18][19] Au + CN − …”

mentioning

confidence: 99%

Electrochemical Quartz Crystal Microbalance Studies of Gold Oxidation in Cyanide Baths

Liu

West

2011

Electrochem. Solid-State Lett.

View full text Add to dashboard Cite

As a means of understanding pulsed reverse plating of gold from cyanide baths, the anodic gold oxidation has been characterized by electrochemical methods, with supplemental information from a quartz crystal microbalance. Dissolution into electrolytes containing excess cyanide and into a gold-cyanide plating bath was compared. Results suggest that in the initial moments after the cathodic portion the dissolution proceeds with a mechanism involving excess cyanide. At longer times, a more complex mechanism leading to an adsorbed AuCN layer on the gold surface prevails. These results may provide guidance in developing plating waveforms for deposited hard gold with desirable properties.The electrodeposition of cobalt hard gold is widely used in connector applications. 1 A major impediment to reducing gold film thickness is the corrosion of the underlying substrate, which is impacted by the porosity of the gold layer. 2 Both the morphology and the hydrogen evolution reaction have significant influence on porosity. 3 Pulsed reverse plating 4-14 can be expected to impact both hydrogen evolution and morphology. A reverse current in cobalt hard gold electroplating may dissolve deposited gold and may oxidize hydrogen produced during the cathodic portion of the waveform. Whether the dissolution of gold and oxidation of hydrogen can be realized depends on the type of plating bath and the plating conditions adapted.A three-step oxidation mechanism for gold in the presence of cyanide has been proposed 15-19However, the potentials at which these reactions occur 18 and the extent of other gold oxidation products, such as trivalent gold formation, 16 remain unresolved. Most studies have been conducted in alkaline solutions, where free cyanide ions are abundant. In weakly acidic solutions, cyanide is associated with hydrogen ions or gold. In reversed pulse plating, the amount of near-surface excess cyanide is changed after the cathodic current is applied, and the oxidation of gold under these conditions has not been fully addressed.With an eye toward optimization of pulsed reverse plating parameters, we present a study of gold oxidation. Experiments are conducted in a KCN solution and in a plating bath. Electrochemical methods and a quartz crystal microbalance ͑QCM͒ ͑Ref. 20-25͒ are employed. In a subsequent paper, we report on the impact of reversed plating parameters on the deposit microstructure and also the porosity. ExperimentalSolutions from a commercial plating bath, Metalor Gold, are used in the study. This Metalor Gold bath contains 0.04 M KAu͑CN͒ 2 , cobalt additives ͑approximately 0.008 M in solution, resulting in around 0.5 wt % of Co in the electrodeposits͒, and supporting electrolyte including conducting salt ͑a mixture of organic acid salt and potassium oxalate monohydrate͒, acid salt ͑citrate based͒, and brightener ͑mixture of potassium hydroxide and aromatic compounds͒. Several solutions, A, B, and a series of C, containing cyanide were employed in this study ͑Table I͒. Estimates of concentrations of cyanide speci...

show abstract

“…No disintegration of the metal was noticed till the last trace of it was dissolved. The third peak was ascribed to the passivation by Au20 3 (MacArthur 1972;Cathro and Koch 1964) and to Au(OHh (Pan and Wan 1979). Both Au203 and Au(OH)3 can dissolve in cyanide solution and hence can result in electropolishing by the mechanism suggested by Hickling and Higgins (1956) and Hoar and Mowat (1950).…”

Section: Resultsmentioning

confidence: 92%

Electrochemical preparation of potassium gold cyanide

Rajagopal

Rajagopalan

1984

Bull. Mater. Sci.

View full text Add to dashboard Cite

The essential requirements for the industrial preparation of potassium gold cyanide (PGC) are: (a) high rate of dissolution and (b) smooth and uniform dissolution. Employing galvanostatic and potentiostatic polarisation data and observations on the surface topography of anodes dissolved by both the techniques, it is shown that potentiostatic dissolution of gold in potassium cyanide at +0-345V satisfies the above requirements.

show abstract

Anodic behaviour of gold in cyanide solution

Cited by 25 publications

References 10 publications

Study on Intensification Behavior of Bismuth Ions on Gold Cyanide Leaching

Study on Intensification Behavior of Bismuth Ions on Gold Cyanide Leaching

Electrochemical Quartz Crystal Microbalance Studies of Gold Oxidation in Cyanide Baths

Electrochemical preparation of potassium gold cyanide

Contact Info

Product

Resources

About