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The industrial use of activated carbon for gold adsorption from alkaline cyanide leach solutions has been a major development in gold hydrometallurgy which was commercialized during the last part of the 20thcentury. In the gold industry, activated carbon is most often used to adsorb gold from dilute alkaline cyanide solutions.
#0183;#32;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.
The Anglo American Research Laboratories AARL carbon stripping system used in this EXAMPLE has two definite advantages when compared with its most common counterpart, the Zadra system. It is much less expensive to operate and it produces a cleaner stripped carbon. It is however very reliant upon the availability of an abundant supply of good quality water and its water usage is far greater
One of the main bottlenecks in the carboninpulp process for the recovery of gold is the elution procedure, which typically requires the heating of caustic cyanide eluants to high temperatures for...
#0183;#32;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.
CPL Activated Carbons supplies the Filtracarb#174; CL range of carbons for the gold mining industry, which independent testing has shown to offer exceptional performance in this application. Our products are characterised by the following properties: High rates of gold loading and elution
size of activated carbons with gold cyanide for subsequent elution experiments as setup in Figure 1. Coarse granular activated carbons were usually washed several times with water and dried overnight at 110#176;C in an oven. Dried coarse activated carbons were then crushed using a mortar and pestle and then wetscreened to different particle size
The process of producing gold AngloGold Ashanti There are two types of mining which take place to access the orebody: Gold adsorbed onto activated carbon is recovered by a process of redissolving the gold from the activated carbon (elution), followed by precipitation in electro winning
The gold cyanide is adsorbed by activated carbon, which is subsequently eluted to produce a concentrated gold solution. The eluted solution is electrowon to recover the precious metals (alternatively, zinc precipitation may be used), and the carbon is treated in a kiln under a flowing steam atmosphere to reactivate its surface for reuse.
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 eluant water quality and eluate flowrates.
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, gold) into the activated carbon granules. Mesopores (100 #197; to 500 #197;) these are the pores that branch off the macropores that serve to allow the adsorbates to leave the macropores
carbon is determined mainly by the pH, temperature and the type of carbon. Cyanide in the pretreatment step will convert the AuCN to reversibly adsorbed Au(CN)2. Competition between cyanide and Au(CN)z for adsorption sites will enhance the elution of gold, but plays a minor role at elevated temperatures. The most important effect of
Elution and Carbon Reactivation Resource book
In the CIL circuit, adsorption of gold onto activated carbon is most effective at low temperatures, low cyanide concentrations, low pH and high gold concentration in solution (although some of these conditions arent practically achievable). By simply reversing these conditions, elution (desorption) of gold from the carbon occurs.
One of the main bottlenecks in the carboninpulp process for the recovery of gold is the elution procedure, which typically requires the heating of caustic cyanide eluants to high temperatures for...
Fundamentals of the elution of gold cyanide from activated carbon. Van der Merwe, Pieter F.(Pieter Francois) (1991) Dissertation (Ph. D. (Ing.)) University of Stellenbosch, 1991. Thesis. ENGLISH ABSTRACT: Most research work on activated carbon systems has been concerned only with the adsorption process.
The validity of a steady state assumption made by Adams and Nicol (1986) in the modelling of the elution of gold from activated carbon was investigated. It is shown that the accuracy of the steady state approximation is dependent, not only on the magnitudes of the solution flow rate and reactor volume, but also on the lumped elution rate constant.
(1992) studied the effect of the alcohol use on gold elutionsuggested that ethanol and lenepropy glycol with NaOH or Na 2 S were effective for eluting the gold from activated carbon loaded gold. Especially, Au was completely eluted by ethanol with NaOH under an optimum condition,, 50vol% of ethanol, of NaOH, 75#176;C and 2hr.
The mechanism of elution of gold cyanide from activated carbon NASA/ADS 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.
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