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the reversibility of adsorption of gold cyanide on

The reversibility of adsorption of gold cyanide on

03/03/2017· The reversibility of the adsorption of gold onto carbon is a function of the nature of the adsorbed gold and determines the need for cyanide in the elution process, which affects the operating costs of a carbon-in-pulp (CIP) plant. The fraction of adsorbed Au(CN) 2 − that will be decomposed to AuCN was found to be a function of the pH and temperature of the solution and the

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The reversibility of adsorption of gold cyanide on

01/06/1993· The reversibility of the adsorption of gold onto carbon is a function of the nature of the adsorbed gold and determines the need for cyanide in the elution process, which affects the operating costs of a carbon-in-pulp (CIP) plant. The fraction of adsorbed Au(CN){ 2 / } that will be decomposed to AuCN was found to be a function of the pH and temperature of the solution and the

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Comparative Study on the Adsorption of Cyanide Gold

Finally, the thermodynamic reversibility of gold adsorption on the carbonaceous adsorbents from an aqueous solution of potassium aurocyanide at room temperature has also been studied. A flow adsorption microcalorimetry method was used to measure the amounts of aurocyanide adsorbed and desorbed in one adsorption−desorption cycle, as well as the corresponding enthalpic changes upon

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Chapter 32 Metallurgist & Mineral Processing Engineer

A key observation is that Au(CN)2- adsorption on carbon is thermodynamically reversible in the absence of CN- ions in solution, as demonstrated over 7 orders FUNDAMENTAL ASPECTS OF GOLD CYANIDE ADSORPTION of magnitude for [Au(CN)2-] (Jones et al., 1988).

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Comparative Study on the Adsorption of Cyanide Gold

09/06/1999· In this paper, adsorption of potassium gold cyanide from water onto three activated carbon samples, four graphites, and two carbon blacks (Graphon and Vulcan) is compared. The present work collects the results of flow microcalorimetric studies for each carbonaceous adsorbent so as to obtain estimates of their polar and accessible apolar graphitic basal plane surface areas.

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Comparative Study on the Adsorption of Cyanide Gold

09/06/1999· In this paper, adsorption of potassium gold cyanide from water onto three activated carbon samples, four graphites, and two carbon blacks (Graphon and Vulcan) is compared. The present work collects the results of flow microcalorimetric studies for each carbonaceous adsorbent so as to obtain estimates of their polar and accessible apolar graphitic basal plane surface areas.

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KINETIC MODEL FOR THE REVERSIBLE ADSORPTION OF

Material balance equations are developed to describe the reversible adsorption of gold cyanide on activated carbon. In this paper the carbon is divided into two interconnected regions with different kinetic characteristics. Equilibrium is assumed to exist between the liquid film surrounding a carbon particle and the gold cyanide adsorbed on the external surface of the carbon. The kinetic model is solved

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Sabinet The mechanism of the adsorption of gold

Although the identity of the gold cyanide adsorbate is not known, the mechanism appears to have an initial adsorption stage that involves the adsorption of an ion pair: Mn+ [Au (CN)2]n where Mn+ is a metal ion (for example Na+, K+ and Ca2+) that has a lower solubility than the Au (CN)2 anion in the adsorption medium, followed by a reduction step in which either a sub-stoichiometric Au (CN)x surface species or

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Mechanism of adsorption of gold and silver species on

01/09/1998· It is interesting that this improvement of gold adsorption on the active carbon occurred while the micropore volume changed little. This suggests that the microporosity does not play a major role in gold cyanide adsorption in agreement with the observed correlation between total pore volume and Au(CN) − 2 adsorption capacity. Although oxygen and nitrogen were introduced into the carbon by

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Themechanism oftheadsorption ofgold cyanide onactivated carbon

believed that gold adsorption is related to specific functional groups or 'points of attachment' on the carbon, they excluded theinvolvement ofbasal planes, carboxylic acidgroups, andbasicoxides. However, they pointed out that aspecial type ofmicropore might be involved. Recently, Choand Pitt21, 22made adetailed investi-gation ofthe factors that influence the adsorption of silver cyanide on

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(PDF) An XPS study of the adsorption of gold (I) cyanide

clear understanding of the mechanism of gold cyanide adsorption on activated . carbon [ 1 ]. One of the main reasons for this may be that commercial activated *Present address: Davy McKee Ltd

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Rate of adsorption of gold cyanide on activated charcoal

The rate of adsorption of gold cyanide on activated charcoal was examined as a function of charcoal concentration and size, temperature, initial gold concentration, pH, and initial concentration of gold on the charcoal. Rate was found to be proportional to temperature, concentration of charcoal and initial gold concentration on charcoal, and to the inverse of charcoal particle size squared.

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Fundamentals of the elution of gold cyanide from

It was now possible to select a carbon on which no irreversibly adsorbed species were formed in order to study the mechanism of the desorption of- gold cyanide and to determine the need for cyanide in the elution process. Although the loaded carbon contained only Au(CN)2, the presence of cyanide was found to drastically enhance the elution of the gold. It was shown that the cyanide present in the elution step

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The leaching and adsorption behaviour of gold ores

2.4.2 Effect of zinc cyanide species on gold leaching 2.4.3 Other metal-cyanide complexes 2.5 PREG-ROBBING OF GOLD 2.5.1 Preg-robbing by carbonaceous matter 2.5.2 Preg-robbing by minerals 2.6 ADSORPTION ONTO ACTIVATED CARBON 2.7 DIAGNOSTIC LEACHING 2.8 BATCH MODELLING 2.8.1 Leaching modelling 2.8.1.1 Empirical models

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Effect of solution chemistry on cyanide adsorption in

05/01/2015· Adsorption of cyanide is increased with temperature from a value of 8.2 mg/g at 20 °C to a value of 28.2 mg/g at 60 °C. It is maximized at pH = 10 (10.5 mg/g), departing from very low values at pH = 8 (less than 1 mg/g) and arriving to intermediate values at pH = 12 (about 7 mg/g). Adsorption is decreased with the increase of the solution ionic strength although the effect is not very pronounced.

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