Activated carbon adsorption of gold from cyanide-starved glycine solutions containing copper. Part 2: Kinetics
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The downstream processing of leachates arising from the dissolution of copper bearing gold ores in cyanide-starved alkaline glycine solutions is imperative for the successful implementation of the new leach system at industry level. This study investigates the behaviour of gold adsorption onto activated carbon in the presence of copper from cyanide-starved glycine solutions. The adsorption behaviour was kinetically investigated using the Fleming k,n model. The model had a high consistency with experimental data (up to 6 h) for both gold and copper as evidenced by the regression coefficient (R2) values which were close to 1. The effects of important parameters including glycine concentration, solution pH, cyanide concentration, initial gold concentration, adsorbent concentration and ionic strength of the solution were studied. The results showed that, except for initial gold and carbon concentrations, a variation of these major factors had a pronounced effect on copper adsorption and slightly affected the gold adsorption, both in terms of adsorption rate and overall recovery. It was also seen that the active carbon had a high adsorption tendency towards gold over copper. The gold and copper extraction from a cyanide-glycine solution containing 2 mg/L gold, 300 mg/L copper, pH 11, 5 g/L glycine, Cu:CN of 1:1 (123 mg/L CN) and 8 g/L carbon using lime as a pH modifier reached 99.0% and 52.8% respectively. Most copper and gold was recovered in the first 6 h. The corresponding initial adsorption rates are 1263.8 h-1for gold and 19.0 h-1for copper.
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Activated carbon adsorption of gold from cyanide-starved glycine solutions containing copper. Part 1: IsothermsTauetsile, P.; Oraby, Elsayed; Eksteen, Jacques (2019)Cyanide-starved alkaline glycine solutions have been shown to have distinct advantages in terms of lower reagent consumption and detoxification needs, or leach rate and recovery, over cyanide- only and glycine-only leach ...
Gold and copper leaching from gold-copper ores and concentrates using a synergistic lixiviant mixture of glycine and cyanideOraby, E.; Eksteen, Jacques; Tanda, B. (2017)© 2017 Elsevier B.V.The presence of cyanide soluble copper in the cyanidation of gold-copper ores and concentrates significantly increases the cyanide consumption in order to achieve sufficient gold recovery. In addition, ...
Oraby, E.; Eksteen, Jacques (2015)© 2015 Elsevier B.V. Abstract In the cyanidation of copper-gold ores, the presence of copper minerals can lead to soluble gold losses, the production of weak acid dissociable (WAD) cyanide, as well as a number of operational ...