Elution of Gold from Activated Carbon Using Supercritical Carbon Dioxide. E. O. Otu. Chemistry. 1997; Abstract A novel method for the desorption of gold from activated charcoal is reported. Ion pair solvation of sodium dicyanoaurate (I) (Na+ … Au(CN)2 − by tributyl-phosphate facilitates the charge …
A plug-flow model is described for the reactor mass balance of a typical AARL gold elution process. The model is in the form of a hyperbolic differential equation and was transformed using the method of characteristics. The transformed model was then solved simultaneously with models dependent on intraparticle surface diffusion and film transfer …
Purchase this Article for $25.00. Parameters affecting gold elution using the AARL process are reviewed and critically analyzed in an attempt to optimise metallurgical efficiency and minimise costs in both current and future carbon adsorption operations. Such factors as acid washing, column geometry, elution temperatures and pretreatment ...
a) Processes for Elution of Aurocyanide frcm Activated Carbon b) Chemistry and Mechanism of Elution of Aurocyanide from Activated Carbon 5.2 Novel Studies on the Mechanism of Elution of Aurocyanide from Activated Carbon 5.3 Kinetics of Elution of Aurocyanide from Activated Carbon a) Effect of Finite, Constant Concentration of Gold …
Gold is an essential metal in the economy and technologies. Most of the gold is produced from mining and cyanidation is the primary method used for gold extraction, with Au(CN) 2-being the product. Activated carbon adsorption has been the primary commercial approach to recover gold from Au(CN) 2-solution since the 1970 s. In the …
The processing of gold solution depends on the adsorption of Au(CN) 2 − onto activated carbon, and its subsequent stripping (or elution) from the activated …
The Anglo elution procedure (Davidson and Duncanson, 1977; Davidson and Veronese, 1979) is an alternative approach, which elutes gold in 8–12 h using deionised water at 100–120 °C. In this procedure, the carbon is pre-soaked with 5% w/v NaCN/1% w/v NaOH solution. This process is sensitive to the quality of water used.
The ZADRA system is another elution process where gold that is adsorbed on to activated carbon is desorbed from the carbon by a reversal of the adsorption kinetics. The ZADRA elution circuit at ...
The elution of gold and silver from activated carbon using organic solvents and the reactivation of the eluted carbon, Anglo American Research Laboratories, Report 6, Johannesburg, 1976. 9 Jankowska, H., Neffe, S. and Swiatkowski, A., Investigations of the electrochemical prop- erties of activated carbon and carbon black, Electrochim.
Activated carbon loaded with gold is then eluted and gold is subsequently recovered by electrochemical methods. Conventional elution processes such as atmospheric and pressurized Zadra processes, involve stripping with a cyanide (0.1–0.2% NaCN) and sodium hydroxide solution (1–2% NaOH) at high temperature (90–140°C) …
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. It is the objective of this article to formulate such a mechanism on the basis of batch and column elution tests without analyzing adsorbed species on the …
The process involves contact of gold laden activated carbon with a strong base at ambient temperatures followed by elution with an aqueous solution containing an organic solvent. Results showed that aqueous solutions of organic solvents, preferably aqueous solution of acetone or acetonitrile could be effectively used in the recovery of …
Evaluating a Dynamic Model for the Competitive Elution of Gold and Base Metals from Activated Carbon. S. P. Liebenberg J. Deventer. Chemistry, Engineering. 1997. Abstract During the past fifteen years significant progress has been made on carbon-in-pulp (CIP) technology for the extraction of gold.
SYNOPSIS. and Analyst. Some of the parameters affecting the elution of gold from freshly loaded activated carbon using pure water as an eluant were studied. The procedure involved pretreatment of the gold-loaded activated carbon with a strong reagent of sodium cyanide and sodium hydroxide, followed by elution of the gold with water.
The initial sodium sulphide elution trial was conducted using 20 g of carbon and 2 L of solution, the ammonium chloride elution involved 50 g of carbon and 2 L of solution with remaining experiments being conducted using 25 g of carbon and 1 L of solution. 50 ml samples were taken periodically, from the elution trials with the volume of liquid ...
The validity of a steady state assumption made by Adams and Nicol (1986) in the modelling of the elution of gold from activated …
The pretreatment of gold-loaded activated carbon with a relatively strong sodium cyanide solution prior to elution with deionized water at 90 to 125i?½Chas been shown to have a …
The presence of spectator cations (M "+) enhances the formation of M"+{Au(CN)~}, 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 con- centration of cations in the eluant is high and no …
The main advantages of activated carbon are its high selectivity towards gold relative to base metals, its ease of elution and its large particle size [13], [14], [15]. ... The confirmatory experiments indicated adsorption efficiency of gold using activated carbon (87.29) under optimal conditions compared with the adsorption rate of 87.11% ...
surface of the activated carbon into the interior. The macropores allow for the rapid movement of adsorbates (species that will be adsorbed by the carbon, e.g. gold) into …
The elution of gold cyanide is suppressed by the presence of cations (M n+) through the formation of M n+ (Au (CN) 2−) 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.
surface of the activated carbon into the interior. The macropores allow for the rapid movement of adsorbates (species that will be adsorbed by the carbon, e.g. gold) into the activated carbon granules. Mesopores (100 Å to 500 Å) these are the pores that branch off the macropores that serve to allow the adsorbates to leave the macropores
The most common reagent used in gold elution from loaded activated carbon is NaOH/NaCN (Phiri, 2019; Snyders et al., 2015). This process is widely applied at the industrial level. The company Jacobi Group offers a full range of carbon products to serve the gold recovery industry.
The Anglo elution procedure ( Davidson and Duncanson, 1977; Davidson and Veronese, 1979) is an alternative approach, which elutes gold in 8–12 h using deionised water at 100–120 °C. In this procedure, the carbon is pre-soaked with 5% w/v NaCN/1% w/v NaOH solution. This process is sensitive to the quality of water used.
Exciting new developments are taking place in the extractive metallurgy of gold, which are based upon the adsorption of the metal or its complexes on carbon and subsequent elution. Despite the efforts of investigators over a period of almost 70 years, however, the mechanisms of the adsorption and elution processes have not yet been …
SYNOPSIS. and Analyst. Some of the parameters affecting the elution of gold from freshly loaded activated carbon using pure water as an eluant were studied. The procedure …
One of the main bottlenecks in the carbon-in-pulp process for the recovery of gold is the elution procedure, which typically requires the heating of caustic cyanide eluants to high temperatures ...
Parameters affecting gold elution using the AARL process are reviewed and critically analyzed in an attempt to optimise metallurgical efficiency and minimise costs in both current and future carbon adsorption operations. Such factors as acid washing, column geometry, elution temperatures and pretreatment reagents are discussed together with …