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Kinetic Model for the Decomposition of Cyanide during the Elution of Gold from Activated Carbon J. S. J. VAN DEVENTER and P. F. VAN DER MERWE DEPARTMENT OF CHEMICAL ENGINEERING UNIVERSITY OF STELLENBOSCH PRIVATE BAG X5018, STELLENBOSCH, 7600, SOUTH AFRICA ABSTRACT Free cyanide is usually present during the elution of gold cyanide from activated

from active carbon surface venter (van De and van der Merwe, 1994). The organic solvent, either ethanol or acetonitrile, is able to increase CN-and Au(CN) 2-activities. As a result, the released ... size of activated carbons with gold cyanide for subsequent elution experiments as set-up in Figure 1. Coarse granular activated

has been made in understanding the mechanisms and kinetics of gold adsorption onto activated carbon (Van Deventer and Van Der Merwe 1994). Alternative processing options that are less energy-intensive and are more able to deal with complex, lower grade ores are in demand, and according to Liddell and Adams (2012), there is

Minerals Engineering, Vol. 7, No. I, pp. 71-86, 1994 0892-.-6875/94 $6.00+0.00 Printed in Great Britain 1993 Pergamon Press Lid FACTORS AFFECTING THE ELUTION OF GOLD CYANIDE FROM ACTIVATED CARBON J.S.J. van DEVENTER and P.F. van der MERWE Department of Metallurgical Engineering, University of Stellenbosch, Private Bag X5018, Stellenbosch, 7600, South Africa .

Van der Merwe [31] with the increase in solution temperature, thereby decreasing the reported that log–log plots of the equilibrium metal loading versus adsorption capacity [36]. the pH for four sets of published data resulted in straight lines in Adsorption of iron cyanide (FeCN) indicated that adsorption all .

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.

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).

P. F. Van Der Merwe's 7 research works with 107 citations and 2,007 reads, including: Kinetic Model for the Decomposition of Cyanide during the Elution of Gold from Activated Carbon

This compares reasonably well with the shape of the elution profiles at this temperature found in the literature (Van der Merwe, 1991). Typical industrial gold elution temperatures range from 110–130°C. As previously been shown in Figure 6, the amount of metal on the carbon affects the rate of adsorption of PGMs onto the carbon.

Fundamentals of the elution of gold cyanide from activated carbon. Van der Merwe, Pieter F.(Pieter Francois) (1991) ... Models were then developed to simulate the changes in· cyanide and potassium concentrations during the elution of the gold cyanide. This enabled the calculation of a shifting gold cyanide equilibrium isotherm as a function of ...

van der Merwe, 1994). ... can be incorporated into a dynamic model describing a continuous shift in the adsorption/desorption equilibrium as elution proceeds.The elution of gold cyanide is ...

desorption of gold and silver from activated carbon Experiments of gold and silver elution were conducted using several parameters, either fixed or varying parameters. Ethanol volume, temperature and percent solid belonged to varying parameters while loaded carbon, stirring rate, concentrations of NaOH and NaCN served as fixed parameters.

Whereas Au(CN){2 /-} is soluble in water, AuCN and Au require the addition of cyanide to form Au(CN){2 /-}. 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.

Cyanide is added to the feed to the CIL at the trash screen under pan to maximise the gold dissolution. Gravity gold is collected and treated by the Knelson concentrators followed by an intensive cyanidation using the ILR3000BA. The In-line Leach Reactor (ILR) was commissioned in December 2012.

The effect of temperature on the desorption of gold cyanide from activated carbon . By van Deventer J.S.J. and van der Merwe P.F. ... 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. ...

A process is disclosed for the recovery of gold and/or silver values from activated carbon, wherein they are adsorbed as cyanide complexes. The process uses an eluant containing sugar. The process allows the eluant to pass through fresh carbon twice, thereby reducing the volume of the gold-loaded eluant. This, in turn, reduces the size of the electrowinning or zinc precipitation circuits.

This compares reasonably well with the shape of the elution profiles at this temperature found in the literature (Van der Merwe, 1991). Typical industrial gold elution temperatures range from 110–130°C. As previously been shown in Figure 6, the amount of metal on the carbon affects the rate of adsorption of PGMs onto the carbon.

Fundamentals of the elution of gold cyanide from activated carbon. [Pieter F Van der Merwe] Home. WorldCat Home About WorldCat Help. Search. Search for Library Items Search for Lists Search for Contacts Search for a Library. Create ...

The mechanism of gold lock-up in refractory wood chips The mechanism of gold lock-up in refractory wood chips Petersen, F.W.; Van Der Plas, P.J.; Van Zyl, C.J. 1997-11-01 00:00:00 Activated carbon has for long been the preferred adsorbent for the recovery of gold from leached slurries. Wood chips, produced by underground blasting, are moved with the gold-bearing material to the carbon-in-pulp ...

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.

(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.

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

The elution of gold from activated carbon using deionized water // Journal of the South African Institute of Mining and Metallurgy. — 1997. ... — ISSN 0038-223X. (англ.) Van Deventer, J. S. J., Van Der Merwe, P. F. The mechanism of elution of gold cyanide from activated carbon // Metallurgical and Materials Transactions B. — 1994.

Discussion on the kinetics of the elution of gold from activated carbon ... The contributions of H. Jacobs and M.F. Van der Merwe who confirmed the findings as part of a final year student project ... Jc = flux of gold cyanide across the outer carbon layer
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