Solution chemistry factors for gold thiosulfate heap leaching

Wan, R. Y.; LeVier, Kristin

doi:10.1016/s0301-7516(03)00107-8

Cited by 58 publications

(27 citation statements)

References 8 publications

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“…Oxygen plays an important role in changing the ratio by oxidizing Cu(I) to Cu(II). Furthermore, the concentration ratio of thiosulfate to ammonia should be maintained in a range of 0.5-1.0 in order to ensure the regeneration of Cu(II), because S 2 O 3 2− and NH 3 are separately the dominant ligands of Cu(I) and Cu(II) in ammoniacal thiosulfate solution [24,43]. Most of above-mentioned reaction conditions are constantly changing during leaching, so it is very difficult to precisely control each of them.…”

Section: The Control Of Reaction Conditionsmentioning

confidence: 99%

“…Lampinen et al [13] demonstrated that satisfactory gold dissolution from a pressure oxidized sulfide gold concentration and negligible thiosulfate consumption can be achieved with low concentrations of ammonia (0.2 M), thiosulfate (0.2 M) and Cu(II) (1.6 mM) under continuous aeration (0.2 L/min air). Based on the literature [12,24,36,45], the mixed pulp potential determined by the Cu(II)/Cu(I) redox equilibrium potential is a key factor for thiosulfate leaching, and there is a proper mixed potential range for both of high gold leaching ratio and acceptable thiosulfate consumption.…”

Section: The Control Of Reaction Conditionsmentioning

confidence: 99%

“…However, the successful commercial application of thiosulfate leaching is almost nonexistent, except that it is being used by Barrick Gold Corporation (Elko, NV, USA) in its Goldstrike deposit with the pretreatment of acidic or alkaline pressure oxidation [21][22][23]. The carbonaceous gold ore in Goldstrike deposit cannot be efficiently leached by cyanidation due to the "preg-robbing" phenomenon, however, this phenomenon does not occur during thiosulfate leaching owing to the very weak affinity of carbonaceous substance for gold thiosulfate complex [24]. This also leads to the problem that the dissolved gold in thiosulfate solution cannot be effectively recovered by active carbon adsorption which is the dominant technique used for pregnant cyanide solution.…”

Section: Introductionmentioning

confidence: 99%

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A Review of Thiosulfate Leaching of Gold: Focus on Thiosulfate Consumption and Gold Recovery from Pregnant Solution

Kong

et al. 2017

Metals

136

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Thiosulfate leaching is a promising alternative to cyanidation, and the main hindrances for its wide commercial application are the high thiosulfate consumption and the difficult recovery of dissolved gold. In this review, the four solutions to reduce the consumption of thiosulfate, including the control of reaction conditions, the use of additives, the generation of thiosulfate in situ, and the replacement of traditional cupric-ammonia catalysis, are introduced and evaluated after the presentation of background knowledge about thiosulfate consumption. The replacement of cupric-ammonia catalysis with other metals, such as nickel-and cobalt-based catalysts, is proposed. The reason is that it not only reduces thiosulfate consumption observably via decreasing the redox potential of leach solution significantly but also is beneficial to gold recovery mainly owing to eliminating the interference of cuprous thiosulfate [Cu(S 2 O 3 ) 3 ] 5− . Based on the comparative analysis for five common recovery techniques of rare-noble metals from pregnant leach solution, ion-exchange resin adsorption is considered to be the most appropriate to recover aurothiosulfate [Au(S 2 O 3 ) 2 ] 3− because the resin can be employed in the form of resin-in-leach/pulp and, furthermore, is able to be eluted and regenerated simultaneously at ambient temperature. At last, how to reduce the process cost of the resin adsorption technique is discussed. In order to simplify the complex two-stage elution process for loaded resins, the traditional catalysis is suggested to be replaced.

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Section: The Control Of Reaction Conditionsmentioning

confidence: 99%

Section: The Control Of Reaction Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Review of Thiosulfate Leaching of Gold: Focus on Thiosulfate Consumption and Gold Recovery from Pregnant Solution

Kong

et al. 2017

Metals

136

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“…However, copper(II), together with the oxygen in the leach liquors, can also catalyze the degradation of thiosulfate, resulting in a high consumption of thiosulfate during gold leaching. The thiosulfate degradation not only leads to higher reagent cost, but also results in the generation of copper sulfide and sulfur layers which can passivate gold and hinder the leaching rate [19][20][21][22]. So the successful application of the thiosulfate leaching technology is obviously restricted by the high thiosulfate consumption and the gold surface passivation.…”

Section: Introductionmentioning

confidence: 99%

Effect of Pyrite on Thiosulfate Leaching of Gold and the Role of Ammonium Alcohol Polyvinyl Phosphate (AAPP)

Liu

Min

et al. 2017

Metals

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Abstract:The effect of pyrite and the role of ammonium alcohol polyvinyl phosphate (AAPP) during gold leaching in ammoniacal thiosulfate solutions were investigated using pure gold foils. The results showed that pyrite catalyzed the decomposition and also significantly increased the consumption of thiosulfate. This detrimental effect became more severe with increasing pyrite content. Further, the presence of pyrite also substantially slowed the gold leaching kinetics and reduced the overall gold dissolution. The reduction in gold dissolution was found to be caused primarily by the surface passivation of the gold. The negative effects of pyrite, however, can be alleviated by the addition of AAPP. Comparison of zeta potentials of pyrite with and without AAPP suggests that AAPP had adsorbed on the surface of the pyrite and weakened the catalytic effect of pyrite on the thiosulfate decomposition by blocking the contact between the pyrite and thiosulfate anions. AAPP also competed with thiosulfate anions to complex with the cupric ion at the axial coordinate sites, and thus abated the oxidation of thiosulfate by cupric ions. Moreover, the indiscriminate adsorption of AAPP on the surfaces of gold and passivation species prevented the passivation of the gold surface by surface charge and electrostatic repulsion. Therefore, AAPP effectively stabilized the thiosulfate in the solution and facilitated the gold leaching in the presence of pyrite.

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“…금 용매제는 인체와 환경에 독성으로 작용하지 않아야 하고 낮은 경비, 그리고 금 정광은 물론 폐 전자부 품에도 폭 넓게 적용해야 한다 (Senanayake, 2004;Barbieri et al, 2010;Syed, 2012). 만일 독성이 없 는 금 용매제를 저 품위 광석에 혹은 방대한 양의 폐 전자부품에 적용한다면 많은 양의 유용금속을 친환경적으로 회수할 수 있을 것이다 (Wan and Levier, 2003;Kozin and Melekhin, 2004).…”

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Mineralogical Phase Transform of Salt-roasted Concentrate and Enhancement of Gold Leaching by Chlorine-hypochlorite Solution

Kim¹,

Cho²,

Oh³

et al. 2013

Journal of the Mineralogical Society of Korea

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: In order to optimize the gold leaching process from refractory sulfide concentrate, a chlorine-hypochlorite solution with varying concentrations and temperatures were applied to salt-roasted concentrate. The concentrate consisted of pyrite, chalcopyrite, and galena, which were turned into hematite through air-roasting at 750℃. Also these concentrates were changed into hematite and nantokite (CuCl)) through salt (NaCl)-roasting at 750℃. The results of the gold leaching experiments showed that the best gold leaching parameters were obtained when the hydrochloric acid-sodium hypochlorite mix was at a ratio of 1 : 2, the added concentration was 1.0 M concentration, the pulp density was 1.0%, and the leaching was done at a 60℃ leaching temperature. The leaching rate for gold was much greater in the roasted concentrate than in the raw concentrate. The leaching rate was greater in the salt-roasted concentrate than in the plain roasted concentrate too. From XRD analysis, quartz was found in the saltroasted concentrate and in the solid residue from the chlorine-hypochlorite leaching solution at 60℃.

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Solution chemistry factors for gold thiosulfate heap leaching

Cited by 58 publications

References 8 publications

A Review of Thiosulfate Leaching of Gold: Focus on Thiosulfate Consumption and Gold Recovery from Pregnant Solution

A Review of Thiosulfate Leaching of Gold: Focus on Thiosulfate Consumption and Gold Recovery from Pregnant Solution

Effect of Pyrite on Thiosulfate Leaching of Gold and the Role of Ammonium Alcohol Polyvinyl Phosphate (AAPP)

Mineralogical Phase Transform of Salt-roasted Concentrate and Enhancement of Gold Leaching by Chlorine-hypochlorite Solution

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