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The elution of gold cyanide is suppressed by the presence of cations Mn through the formation of Mn AuCN2- on the carbon. The horizontal position of the gold peak in an AARL elution profile was found to be a function of the elution of the cations from the carbon bed.
van De venter, J.S.J. and van der Merwe, P.F., 1994, Factors affecting the elution of gol d . ... Free cyanide is usually present during the elution of gold cyanide from activated carbon. The ...
van Deventer J.S.J. van der Merwe P.F. 1993 Article. Activated carbon is used worldwide for the extraction of gold cyanide from leached pulps. The elution of gold cyanide is usually conducted by soaking the loaded carbon in an alkaline solution of cyanide in a column, followed by a rinse with water at temperatures higher than 100 C. ...
Van Der Merwe and Van Deventer, 1988, Cho et al. ... Electro winning of gold cyanide is, however, ... Chemistry of adsorption and elution of gold on activated carbon, Recent developments in .
By van Deventer J.S.J., Lorenzen L., van der Merwe P.F., Morrison D.W. and van der Westhuysen J.P.W. Abstract. ... An equilibrium model can be used for the elution of gold activated carbon in which the equilibrium isotherm shifts as cyanide and spectator cations are removed, and the surface of the carbon is reactivated by removal of the cyanide ...
van Deventer, J. S. J. and van der Merwe, P. F. 1994 Factors affecting the elution of gold cyanide from activated carbon, Minerals Engineering, 71, pp. 7186. doi 10.10160892-68759490148-1. Elnathan, F. 2007 The effect of activated carbon particle size on gold cyanide adsorption and elution. University of Utah.
Van Deventer and Van der Merwe 1994 developed a generalised model to simulate the more complex AARL process. Equilibrium conditions may be assumed in an elution column when adsorption is weak, while diffusional phenomena become rate controlling when desorption is weak towards the end of a elution cycle. o 5 10 15 BEDVOLUMES
Van Deventer and Van der Merwe ... but it was still found that it is the cyanide anion in the pre-treatment step that enhances the elution of gold, and not the cyanide anion that is carried over ...
Elution model For the sake of clarity the elution model proposed by Adams and Nicol 1986 and Adams 1990 is given. It was proposed that the rate of elution could be described by the rates of mass transfer of gold di-cyanide in the outer layer of the carbon particle and in the solution film surrounding the particle. The rate
08-03-2019 application of pg boilers in gold elution Industrial Boiler Supplier AARL GOLD ELUTION FLOWSHEET . ... J. South Afr. Inst. Min. Metall., v. 79, n. 19, pp. 437-445, The mechanism of elution of gold cyanide from activated carbon. Titre du document Document title The mechanism of elution of gold cyanide from activated carbon ...
The pretreatmenty of gold-loaded activated carbon with a relatively strong sodium cyanide solution prior to elution with deionized water at 90 to 125 degree C has been shown to have a most ...
Experiments of gold and silver elution were conducted using several parameters, either fixed or varying ... van sDeventer and van der Merwe, 1994. Experiments for goldsilver - ... size of activated carbons with gold cyanide for subsequent elution experiments as set-up in Figure 1. Coarse granular activated
van Deventer J.S.J. van der Merwe P.F. 1994 Article Functional relationships were determined between the effects of pH, temperature, and the concentrations of cyanide and cations on the gold cyanide equilibrium during elution from activated carbon in columns and in batch reactors.
By van Deventer J.S.J. and van der Merwe P.F. Abstract. Activated carbon is used worldwide for the extraction of gold cyanide from leached pulps. The elution of gold cyanide is usually conducted by soaking the loaded carbon in an alkaline solution of cyanide in a column, followed by a rinse with water at temperatures higher than 100 C. ...
Much controversy exists about the mechanism by which gold cyanide adsorbs on activated carbon. It is not the purpose of this article to explain the exact adsorption mechanism but, rather, to investigate the factors affecting the reversibility of adsorbed gold cyanide. Whereas AuCN 2 is soluble in water, AuCN and Au require the addition of cyanide to form AuCN 2 .
During the past fifteen years significant progress has been made on carbon-in-pulp CIP technology for the extraction of gold. While most research on the mechanisms and kinetics of CIP sub-processes has focused on the adsorption step only, auxiliary unit operations such as elution, acid washing and the thermal regeneration of spent carbon have received less attention.
Whereas AuCN2 - is soluble in water, AuCN and Au require the addition of cyanide to form AuCN2 -. 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.
Sep 23, 2006 Abstract. Free cyanide is usually present during the elution of gold cyanide from activated carbon. The decomposition of cyanide is important not only in the extraction of gold but also for environmental reasons.
Designing gold extraction processes Performance study of . Aug 01, 2017amp 0183amp 321. Introduction. The governing method for gold ore processing has been cyanide leaching since the late 19th century Marsden and House, 2006 .After decades of active development of the process for various types of ores and concentrates, there are several different hydrometallurgical flowsheets for cyanide leaching.
The presence of zinc in solutions leads to an overestimation of free cyanide due to the low stability of zinc-cyanide complexes compared with silver-cyanide Koc et al., 2014 Van der Van der Merwe ...
point, and experiments suggest the possibility of an optimum cyanide concentration, beyond which elution efficiency starts decreasing. Introduction The carbon-in-pulp or carbon-in-leach CIP and CIL processes have been the main commercial processes on almost every gold plant built since 1980 Fleming, 1992 Van Deventer, 1984.
In the presence of copper cyanide, the elution order has been found to be copper, palladium, platinum and gold, which is the opposite order of adsorption preference. ... The dependency of the platinum elution rate on the sodium concentration on the activated carbon, as suggested by gold related literature Van Der Merwe and Van Deventer, 1990 ...
The elution of the gold cyanide was found to be diffusion controlled only under conditions of weak desorption. Under these conditions, the desorption of the gold cyanide was simulated with a model accounting for mass transfer between the micropores and the macropores of the carbon, surface diffusion in the macropores, and film diffusion through the liquid layer surrounding the carbon particles.
Jan 01, 1994 This can be attributed to mainly two factors a Although the acid washed carbon was washed with distilled water before it was added to the cyanide solution, enough acid was left on the carbon to destroy a large percentage of the cyanide that would have been utilised for the desorption of the gold, and b the acid lowered the pH of the eluant from approximately 10 for the non-acid washed carbon to 9 for the acid washed carbon.
Van der Merwe 1991 and Stange 1991 showed that the elution of gold is dependent on the removal of the sodium or potassium introduced in the pre-treatment step. The extent of cyanide decomposition determines the passivation of the carbon surface and the decrease in the equilibrium isotherm for gold loading Van der Merwe, 1991.
Dec 01, 1994 The mechanism of elution of gold cyanide from activated carbon. van Deventer, J. S. J. van der Merwe, P. F. Abstract. Numerous articles have appeared on the mechanism of the adsorption of gold cyanide onto activated carbon. In contrast, little information is available on the mechanism of elution of the adsorbed gold.
Feb 01, 1994 Van der Merwe, P.F., Fundamentals of the elution of gold cyanide from activated carbon, Ph.D. Thesis, University of Stellenbosch, South Africa, 453 1991. Stange, W. amp King, R.P., The optimization of the CIP process, Proceedings of XXll International APCOM Symposium, Berlin, Germany, 371-382 1990.
Dec 01, 1994 The presence of spectator cations M n enhances the formation of M n Au CN 2 n ion pairs on the carbon, which in turn suppress the elution of gold cyanide. The dynamics of removal of these cations determine the horizontal position of the gold peak in an elution profile. When the concentration of cations in the eluant is high and no cyanide is present in the solution or on the
The elution of gold cyanide is usually conducted by soaking the loaded carbon in an alkaline solution of cyanide in a column, followed by a rinse with water at temperatures higher than 100 C. Because the effects of temperature, cyanide addition and ionic strength are confounded to an extent, little has been published with which to model the dynamic behaviour of this complex process.
van der Merwe, P. F. Much controversy exists about the mechanism by which gold cyanide adsorbs on activated carbon. It is not the purpose of this article to explain the exact adsorption mechanism but, rather, to investigate the factors affecting the reversibility of adsorbed gold cyanide.
Fundamentals of the elution of gold from activated carbon, PhD thesis, University of Stellenbosch Van Deventer, J.S.J, Van der Merwe, P.F, 1994. Factors affecting the elution of gold cyanide from activated carbon, Minerals Engineering, 71, pp. 71-86 Van Deventer, J.S.J. 1984.
Van der Merwe, 1991. During the electrowinning procedure, gold metal is recovered by an electrolytic process, whereby the gold deposits onto the cathode. The laden gold cathodes may contain 7075 gold and 10-15 silver, the remaindPf being copper and steel wool.
Optimisation of Operating Parameters for Cyanidation of Sulfide-Bearing Gold Flotation Tailings in order to Prevent the Impact of Cyanicides By Fa al Larachi The application of activated carbon for the adsorption and elution of platinum group metals from dilute cyanide leach solutions
The kinetics of elution of gold cyanide from activated carbon Hydrometallurgy Fundamentals, Technology and Innovation, Eds J.B. Hiskey and G.W. Warren, TMS, pp. 459-473 1993 Other authors
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According to Van Deventer, the presence of spectator cations Mn n enhances the formation of Mn n AuCN 2- n ion pairs on the carbon, which in turn suppresses the elution of gold cyanide. When the concentration of cations in the eluant is high and cyanide is absent from the solution or the carbon, very little desorption of gold is observed.