Abstract
The use of galvanic interactions between zero-valent aluminum (ZVAl) and activated carbon (AC) to recover gold (Au) ions is a promising technique to overcome the challenges due to the poor recovery in ammonium thiosulfate systems, but the applicability to practical Au ore processing remains elusive so far. The present study describes (1) the recovery of Au ions from low Au concentrations, which are typical concentrations used in Au ore processing; and (2) an investigation into the effects of various coexisting base metal ions that can be present in pregnant ore-leached solutions. The results showed that high Au recovery (i.e., over 85%) was obtained even at low Au concentrations under the following conditions: 1:1 of 0.15 g of ZVAl and AC with 10 mL of ammonium thiosulfate solution containing 5 mg/L of Au ions at 25 °C for 1 h in an anoxic atmosphere. Selected coexisting metal ions (i.e., copper, iron, cobalt, nickel, and zinc) were studied to establish their effects on Au recovery, and the results showed that the Au recovery was enhanced (about 90%) when copper ions coexist in the solution with minimal effects from other competing base metal ions.
Highlights
Division of Sustainable Resource Engineering, Faculty of Engineering, Hokkaido University, Department of Mining, Chemical and Metallurgical Engineering, Faculty of Engineering, School of Minerals and Energy Resource Engineering, The University of New South Wales, Tel.: +81-11-706-6918 (S.J.)
The results indicate that recovery slightly decreases as the initial concentrationwas decalculated according the following equation: creases, similar to thetoresults reported by Wang et al [29] and Nguyen et al [30] for the cementation of Au ions, but still showed a high recovery of 90%
The results showed that in the absence of Cu ions, Au recovery increased to 83% with the addition of 10 mM of Ni ions, recovery decreased as the addition of Ni ions increased by the competitive reduction
Summary
The use of galvanic interactions between zero-valent aluminum (ZVAl) and activated carbon (AC) to recover gold (Au) ions is a promising technique to overcome the challenges due to the poor recovery in ammonium thiosulfate systems, but the applicability to practical Au ore processing remains elusive so far. The present study describes (1) the recovery of Au ions from low Au concentrations, which are typical concentrations used in Au ore processing; and (2) an investigation into the effects of various coexisting base metal ions that can be present in pregnant ore-leached solutions. Among the many alternative methods for Au extraction, copper (Cu)-catalyzed ammonium thiosulfate leaching is one of the most promising because it uses lixiviants that are non-toxic and less corrosive (Equation (1)) [4,5]
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