gold dissolution and activation in cyanide solution

Gold dissolution and activation in cyanide solution ...

01/08/2000  The dissolution rate of gold in clear cyanide solution has been examined using a rotating disk gold electrode. The dissolution rate appears to be controlled by reactions occurring on the gold surface. The activator NMI was found to enhance the dissolution rate. As activator concentration increases, the rate first increases and then decreases, suggesting competitive adsorption between the ...

Get PriceEmail contact

Gold dissolution and activation in cyanide solution ...

The dissolution rates were independent of electrode rotation speed for air-saturated solutions and cyanide concentrations above 5 mol m −3 and were well below external mass transfer-limited rates for cyanide and oxygen. An activator molecule, NMI, was shown to increase the rate of dissolution and served to illustrate the importance of surface reactions in the dissolution mechanism. With ...

Get PriceEmail contact

Gold dissolution and activation in cyanide solution ...

Gold dissolution and activation in cyanide solution: Kinetics and mechanism. August 2000 ; Hydrometallurgy 57(1):1-11; DOI: 10.1016/S0304-386X(00)00084-0. Authors: M. E

Get PriceEmail contact

(PDF) Gold dissolution and activation in cyanide solution ...

The activation energy for the anodic dissolution of gold in aqueous alkaline cyanide solution has been reported to be in the range of 47-55 kJ y1 w x mol 12,13 . In contrast, typical activation energies for diffusion controlled reaction range between 5 and 20 kJ mol y1 .A further indication that surface kinetics control the rate of gold dissolution is the observation that rate increases in the ...

Get PriceEmail contact

Kinetics of enhanced gold dissolution: activation by ...

29/09/2003  Mechanism and rate-controlling factors in the dissolution of gold in cyanide solution. J. Met., 6 (1954), pp. 541-548. View Record in Scopus Google Scholar. Nicol, 1980 Nicol, M.J., 1980. The anodic behaviour of gold. Gold Bulletin, Part II—Oxidation in Alkaline Solutions, 13, pp. 105–111. Google Scholar. Sawaguchi et al., 1995. S. Sawaguchi, T. Yamada, Y. Okinaka. Electrochemical

Get PriceEmail contact

Kinetics and Mechanism of Gold and Silver Dissolution In ...

Activation energy for the dissolution reaction of gold, silver, and copper in cyanide solutions . . 20 11. Solubility of minerals and metals in cyanide solutions..... 23 12. Estimated values of diffusion coefficients ..... 33 13. Thickness of boundary layer calculated according to equation..... 35 iv John Stewart MacArthur Robert Wardrop Forrest, M, D. Portraits of the inventors of cyanidation ...

Get PriceEmail contact

Kinetics and reaction mechanism of gold cyanidation ...

01/11/2005  Gold dissolution and activation in cyanide solution: kinetics and mechanism. Hydrometallurgy, 57, 1–11.], which considered the mass transfer away from the active crystalline gold

Get PriceEmail contact

Kinetics and mechanisms of gold dissolution by ferric ...

01/01/2018  Gold dissolution was investigated in ferric chloride solution, being one alternative cyanide-free leaching media of increasing interest. The effect of process variables ([Fe 3+] = 0.02–1.0 M, [Cl −] = 2–5 M, pH = 0–1.0, T = 25–95 °C) on reaction mechanism and kinetics were studied electrochemically using rotating disk electrode with ω cyc = 100–2500 RPM and Tafel method.

Get PriceEmail contact

Kinetics of enhanced gold dissolution: activation by ...

29/09/2003  Mechanism and rate-controlling factors in the dissolution of gold in cyanide solution. J. Met., 6 (1954), pp. 541-548. View Record in Scopus Google Scholar. Nicol, 1980 Nicol, M.J., 1980. The anodic behaviour of gold. Gold Bulletin, Part II—Oxidation in Alkaline Solutions, 13, pp. 105–111. Google Scholar. Sawaguchi et al., 1995. S. Sawaguchi, T. Yamada, Y. Okinaka. Electrochemical

Get PriceEmail contact

Understanding gold nanoparticle dissolution in cyanide ...

The electrochemical dissolution of citrate-capped gold nanoparticles (AuNPs) was studied in cyanide (CN −) containing solutions. It was found that the gold nanoparticles exhibited different dissolution behaviours as ensembles compared to the single particles. At the single particle level, a nearly complete oxidation of 60 nm AuNPs was achieved at concentrations greater than or equal to 35.0 ...

Get PriceEmail contact

DISSOLUTION OF GOLD WITH CYANIDE REPLACING REAGENTS

Dissolution of gold in cyanide solution is shown in Eq. 1. At low cyanide concentrations, the dissolution rate is a function of cyanide concentration. At high cyanide concentrations the dissolution rate of reaction -4 Au + 8 CN + O 2-+ 2 H 2O ↔ 4 Au(CN) 2-+ 4 OH (1) is a function of oxygen concentration (Deschenes, 2005). Dissolution of gold in alkaline thiosulfate solution is shown in Eq.

Get PriceEmail contact

Dissolution of gold with cyanide replacing reagents ...

Gold dissolution was investigated in ferric chloride solution, being one alternative cyanide-free leaching media of increasing interest. The effect of process variables ([Fe³⁺] = 0.02–1.0 M ...

Get PriceEmail contact

(PDF) Electrochemistry of conventional gold cyanidation ...

Key’ords: Gold; Conventional gold cyanidation; Gold anodic dissolution; Oxygen reduction on gold; Mixed potential 1. Introduction despite the intense research works in this field, gold leaching with cyanide solutions has not substantially The dissolution of gold in aqueous cyanide solutions changed. is known since XVIII century. Scheele in 1783 and Thirty years ago, Habashi [I] published

Get PriceEmail contact

Cyanide Leaching Chemistry Gold Cyanidation

The reactions that take place during the dissolution of gold in cyanide solutions under normal conditions have been fairly definitely established. Most agree that the overall cyanide equation for leaching and cyanidation of gold is as follows: 4 Au + 8 NaCN + O2 + 2 H20 = 4 NaAu(CN)2 + 4 NaOH

Get PriceEmail contact

Kinetics and mechanism of the gold corrosion dissolution ...

data [2] on the gold dissolution rate in cyanide solutions (curve 2). When diluting the solution, the chloride ion concentration was decreased to 4.71% (47.1 g/l); the pH value was controlled by adding HCl (ultra-high purity grade). We see that the pH dependence of the free-corrosion dissolution rate (v Au) in the chloride– hypochlorite solutions is rather complicated. At extremely low pH ...

Get PriceEmail contact

MODELING OF GOLD CYANIDATION

The chemistry of gold dissolution in alkaline cyanide solution has continually received attention and new rate equations expressing the gold leaching are still developed. The effect of leaching parameters on gold cyanidation is studied in this work in order to optimize the leaching process. A gold leaching model, based on the well-known shrinking-core model, is presented in this work. It is ...

Get PriceEmail contact

Gold cyanidation - Wikipedia

Gold cyanidation (also known as the cyanide process or the MacArthur-Forrest process) is a hydrometallurgical technique for extracting gold from low-grade ore by converting the gold to a water-soluble coordination complex.It is the most commonly used leaching process for gold extraction.. Production of reagents for mineral processing to recover gold, copper, zinc and silver represents ...

Get PriceEmail contact

Recovery of Gold and Silver and Removal of Copper, Zinc ...

18/01/2015  Early studies on the dissolution of gold in cyanide solution in the presence of sulfide minerals have shown that heavy metal components, such as Cu, Pb, Fe and Zn cyanide ions, significantly increase the consumption of both cyanide and oxyg[1] [2]. In addition, en the sulfide component has been shown to have a strong impact on the gold leaching kinetics [5]. The leac[3]- h-

Get PriceEmail contact

Electrochemical study of gold dissolution in cyanide

The dissolution of gold in alkaline solutions containing cyanide ions is of great importance and its application in the MacArthur-Forrest process towards the end of the last century revolutionized ...

Get PriceEmail contact

DISSOLUTION OF GOLD WITH CYANIDE REPLACING REAGENTS

Dissolution of gold in cyanide solution is shown in Eq. 1. At low cyanide concentrations, the dissolution rate is a function of cyanide concentration. At high cyanide concentrations the dissolution rate of reaction -4 Au + 8 CN + O 2-+ 2 H 2O ↔ 4 Au(CN) 2-+ 4 OH (1) is a function of oxygen concentration (Deschenes, 2005). Dissolution of gold in alkaline thiosulfate solution is shown in Eq.

Get PriceEmail contact

Dissolution of gold with cyanide replacing reagents ...

Gold dissolution was investigated in ferric chloride solution, being one alternative cyanide-free leaching media of increasing interest. The effect of process variables ([Fe³⁺] = 0.02–1.0 M ...

Get PriceEmail contact

(PDF) Electrochemistry of conventional gold cyanidation ...

Key’ords: Gold; Conventional gold cyanidation; Gold anodic dissolution; Oxygen reduction on gold; Mixed potential 1. Introduction despite the intense research works in this field, gold leaching with cyanide solutions has not substantially The dissolution of gold in aqueous cyanide solutions changed. is known since XVIII century. Scheele in 1783 and Thirty years ago, Habashi [I] published

Get PriceEmail contact

MODELING OF GOLD CYANIDATION

The chemistry of gold dissolution in alkaline cyanide solution has continually received attention and new rate equations expressing the gold leaching are still developed. The effect of leaching parameters on gold cyanidation is studied in this work in order to optimize the leaching process. A gold leaching model, based on the well-known shrinking-core model, is presented in this work. It is ...

Get PriceEmail contact

Kinetics and mechanism of the gold corrosion dissolution ...

data [2] on the gold dissolution rate in cyanide solutions (curve 2). When diluting the solution, the chloride ion concentration was decreased to 4.71% (47.1 g/l); the pH value was controlled by adding HCl (ultra-high purity grade). We see that the pH dependence of the free-corrosion dissolution rate (v Au) in the chloride– hypochlorite solutions is rather complicated. At extremely low pH ...

Get PriceEmail contact

Gold leaching in cyanide-starved copper solutions in the ...

gold dissolution from leaching a pure gold disc (2.27 cm2) after 2 h, for each step, is shown in Fig. 2. It can be seen that increasing the pH of cuprous cyanide solutions (step 2) enhances the dissolution of gold using Cu(CN) 2 − solutions at a rate two times higher than at pH 10.5. At

Get PriceEmail contact

Recovery of Gold and Silver and Removal of Copper, Zinc ...

18/01/2015  Early studies on the dissolution of gold in cyanide solution in the presence of sulfide minerals have shown that heavy metal components, such as Cu, Pb, Fe and Zn cyanide ions, significantly increase the consumption of both cyanide and oxyg[1] [2]. In addition, en the sulfide component has been shown to have a strong impact on the gold leaching kinetics [5]. The leac[3]- h-

Get PriceEmail contact

Gold dissolution and copper suppression during

To decrease the cyanide consumption, cyanide is added into the leach solutions to maintain a ratio of cyanide to total reactive copper (CN/Cu) below 2. At low CN/Cu ratio, increasing the pH of solution can lead to the precipitation of solubilized copper as CuO/Cu(OH)2, releasing cyanide ions for further both gold and copper dissolution. A comparison of leaching gold in cyanide–caustic ...

Get PriceEmail contact

Modelling and simulation of gold ore leaching

consists of spraying a cyanide solution on a roughly crushed ore pile. In this approach, cyanide and oxygen diffuse slowly through the pores and fractures of the ore to reach gold surfaces. Several authors studied gold dissolution kinetics. Some considered pore diffusion transport in heap leaching (Prosser1, Bouffard and Dixon2) while others addressed the leaching problem by the concept of ...

Get PriceEmail contact

Copyright © 2020.Company name All rights reserved.SiteMap