An innovative thiourea gold leaching process

Ubaldini, Stefano; Fornari, P.; Massidda, R.; Abbruzzese, C.

doi:10.1016/s0304-386x(97)00076-5

Cited by 121 publications

(55 citation statements)

References 4 publications

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“…The presence of 5 g/L Fe 2 (SO 4 ) 3 in the mixture of thiourea and sulfuric acid improved the dissolution of silver 7.9 to 49.0%. This is ascribed to the slower formation kinetics of formanidine disulphide, which will hinder the dissolution of silver and gold, with ferric ions than hydrogen peroxide 2) . Furthermore, some of thiourea can be oxidized by ferric ion to form either ), which passivates the surface of the metals and thus prevents the leaching of gold 29,31) .…”

Section: Leaching With Thioureamentioning

confidence: 99%

“…The disadvantages of thiosulfate and thiourea are the high consumption of reagent and the high price of oxidants. Since the related problems have not been solved, thiosulfate and thiourea systems have not been applied to commercial operation 2) . In our previous works on the leaching of gold and silver from anode slime resulted from the recovery of copper, various inorganic reagents and the mixture of HCl and some oxidizing agents were employed to find an efficient leaching system to dissolve both gold and silver from the anode slime 20,21) .…”

Section: Introductionmentioning

confidence: 99%

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Leaching of the Mixture of Metallic Gold and Silver

Xing¹,

Lee²

2017

Journal of the Korean Institute of Resources Recycling

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주제어 : 금, 은, 염산, thiosulfate, thiourea, AbstractIn order to exclude the effect of uneven distribution of gold in anode slime, the dissolution of gold and silver from the metal mixture was investigated in different systems, such as the mixture of hydrochloric acid and oxidizing reagents (H , Au was completely dissolved but the leaching percentage of Ag was around 1%. In both thiosulfate and thiourea solution, gold was not dissolved at all. The presence of ferric ion in acidic thiourea solution showed a favorable effect on the leaching of silver but further study is necessary to elucidate the combined effect of ferric ion and sulfuric acid.

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Section: Leaching With Thioureamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Leaching of the Mixture of Metallic Gold and Silver

Xing¹,

Lee²

2017

Journal of the Korean Institute of Resources Recycling

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“…, H 2 O 2 , EDTA and sodium citrate etc are investigated [12][13][14][15][16][17][18][19][20] . However, during the leaching process, some decomposition was caused due to the presence of oxidants and some new compounds were formed resulting in the high consumption of thiourea and thiosulfate.…”

Section: +mentioning

confidence: 99%

Leaching of Gold and Silver from Anode Slime with Inorganic Reagents

Xing¹,

이기웅²,

Lee³

2017

Journal of the Korean Institute of Resources Recycling

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) together with thiourea and thiosulfate solution to recover gold and silver. Gold was not dissolved at all into these inorganic acids in the absence of any oxidizing agents. At the same concentration of inorganic acid, the leaching of percentage of Ag was the highest in the sulfuric acid solution. The leaching percentage of silver increased with the increase of HCl concentration owing to the formation of AgCl 2 − . Copper, nickel and zinc except tin was almost dissolved in these inorganic acids but no tin was dissolved in nitric acid solution. Most of Au and Ag were dissolved into the mixture of sulfuric acid and thiourea solution. Thiosulfate could dissolve some silver from the anode slime but no gold was dissolved by this agent.

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“…Since higher dissolution rates mean smaller leaching tanks, investment costs and energy consumption can be reduced [12,13]. The use of thiourea and thiosulfate has been mainly applied to refractory gold and silver ores, in addition to other metals of interest, such as Cu, Pb and Zn, as traditional processes have shown certain deficiencies when treating such minerals [14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%