Thiosulfate leaching of gold from a mechanically activated CuPbZn concentrate

Ficeriová, Jana; Baláž, Peter; Boldižárová, E.; Jeleň, Stanislav

doi:10.1016/s0304-386x(02)00135-4

Cited by 48 publications

(16 citation statements)

References 10 publications

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“…However, the gold extraction from a low grade rhyolite ore which contained high grade silver (3 g/t Au, 113 g/t Ag) and MnO 2 was enhanced at a moderate temperature of 40°C (2). Mechanical activation has been used to improve the extraction of gold and silver from complex sulfide ores by using copper sulfate and ammonium thiosulfate at pH close to 6 and an elevated temperature of 70°C (31,32).…”

Section: Selected Leaching Resultsmentioning

confidence: 99%

The role of ligands and oxidants in thiosulfate leaching of gold

Senanayake

2005

Gold Bull

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The widely used cyanidation technology is not applicable to some gold ores due to economic or technical reasons when the cyanidation gives very low gold extractions. Despite the fact that the gold mining industry accounts for only 13% of total cyanide consumption there is growing public concern over the use of toxic cyanide for gold extraction. Many researchers have identified that thiosulfate leaching is the most likely alternative to cyanidation due to nontoxicity, low cost and other benefits. This article describes the current information on stoichiometric relationships, equilibria, reaction rates and mechanisms related to anodic or chemical oxidation of gold in thiosulfate, ammoniacal thiosulfate and ammoniacal copper(II) thiosulfate solutions in the presence or absence of oxygen. Gold Bulletin 2005 • 38/4 170 Selected leaching resultsUnlike gold cyanidation, thiosulfate leaching involves relatively high concentrations of reagents, while the gold extraction is largely dependent on the presence or absence of various background reagents. The complexity of thiosulfate leaching of gold is exemplified in Figure 1 (14). It shows that sulfite, sulfide, sulfate glycine and ethylenediaminetetracetic acid (EDTA) have beneficial effects on gold extraction, compared to standard thiosulfate leaching with 0.03 M copper sulfate, 0.3 M sodium thiosulfate and 3 M ammonia (pH 10.2) in the absence of these additives. The oxidation of thiosulfate by copper(II) and/or oxygen during leaching produces tetrathionate (S 4 O 6 2-), trithionate (S 3 O 6 2-) and sulfate as byproducts and increases thiosulfate consumption under some conditions. Reagents such as EDTA, sodium sulphide, and sodium sulfite lower the thiosulfate consumption (Fig. 1). While a moderate ammonia concentration up to 4 M is beneficial, a higher concentration of ammonia is detrimental for gold leaching (4). As shown in Figure 2 the increase in pH from 9 to 10 is beneficial for gold extraction (12). However, the increase in pH also causes an increase in thiosulfate consumption as shown in Figure 3, especially at high thiosulfate dosages (2). Figure 4 shows the beneficial or detrimental effect of increasing temperature depending on the type of gold ore. The detrimental effect of high temperatures on gold extraction from an oxide ore (83 Au g/t + SiO 2 , K, Na, Al, Mg, Si, AlOOH) has been related to the passivation caused by the reaction between copper(II) and thiosulfate, leading to the formation of copper(II) sulfide (4). The gold extraction from a sulfide concentrate reached a maximum at 60°C (3). However, the gold extraction from a low grade rhyolite ore which contained high grade silver (3 g/t Au, 113 g/t Ag) and MnO 2 was enhanced at a moderate temperature of 40°C (2). Mechanical activation has been used to improve the extraction of gold and silver from complex sulfide ores by using copper sulfate and ammonium thiosulfate at pH close to 6 and an elevated temperature of 70°C (31, 32).Thiosulfate leaching is also sensitive to mineralogy because reactive su...

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Section: Selected Leaching Resultsmentioning

confidence: 99%

The role of ligands and oxidants in thiosulfate leaching of gold

Senanayake

2005

Gold Bull

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“…Several promising experimental investigations [84][85][86]88,89,[99][100][101][102][103] have been undertaken. The stability constants for thiosulfate in comparison with various other gold complexes are shown in Table 6.…”

Section: Thiosulfate Leachingmentioning

confidence: 99%

“…Thiosulfate (S 2 O 3 2− ), a chemical used widely in photography and in the pharmaceutical industries, has also been proposed as a substitute for cyanide by many researchers [81][82][83][84][85][86][87][88][89][90][91][92][93][94][95][96][97].…”

Section: Thiosulfate Leachingmentioning

confidence: 99%

Metallurgical recovery of metals from electronic waste: A review

Cui

Zhang

2008

Journal of Hazardous Materials

1,494

685

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“…Many research works have been carried out on mechanical alloying and mechanical activation kinetics and the way which mechanical energy affects the reaction rate. There are studies on the kinetics of thermal decomposition of mechanically activated compounds [2,4,5], chemical leaching of mechanically activated minerals [6][7][8] and formation of solid solution and/or amorphous alloys by mechanical alloying, and crystallization of the as-milled amorphous powders [9][10][11][12][13][14]. However, the activation energies and mechanisms of displacement reactions as a function of milling time need more investigation.…”

Section: Introductionmentioning

confidence: 99%