Previous studies have addressed the effect of the initial pH of the chloride —hypochlorite solution on the leaching of the gold present in the sulphide ores. ... İpekoğlu Ü (2005) Leaching of Ovacık gold ore with cyanide, thiourea and thiosulphate. Miner Eng 18(3):363–365. Article Google Scholar Baghalha M (2007) Leaching of an oxide ...
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Au (solution) is the amount of gold in the thiourea solution, Au (solid) is the amount of gold in the feed sample before the leaching process, and Vt is the total volume of solution (l), and [Au ...
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Whereas some accompanying elements like Se, Te, V, Cr and Ni in the concentrate were insoluble in the acidic thiourea solution. Gold was recovered from the leach liquor by adsorption on the ...
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Additives such as reducing agents or complexing agents are usually used for stabilization of thiourea in solutions. As has been reported [9], [17], the consumption of thiourea was significantly decreased after the introduction of SO 2 gas or the addition of Na 2 SO 3 into thiourea leaching solution. However, the SO 2 is a toxic gas and the use of Na 2 SO 3 can …
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Leaching with a relatively concentrated thiourea solution (1MCS (NH 2) 2) resulted in 83% gold and 75% silver extraction in four hours. With the treated flue dust residue, gold extraction was …
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Prior to leaching, the gold concentrate was subjected to a series of washes and cleaning with CaClO 3, and regulating the pH with Ca(OH) 2. In addition, oxygen was used as oxidant agent for cyanide leaching, and H 2 SO 4 as oxidant agent for thiourea leaching. The control of the potential of solution was performed using a multimeter connected ...
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The next step after leaching in the hydrometallurgical gold processing is the recovery of gold from the solution. In the gold mining industry, activated carbon is the most widely used extractant to recover gold from pregnant cyanide leach solution, known as carbon-in-leach (CIL), carbon-in-pulp (CIP), and carbon-in-columns (CIC) processes ...
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Several studies on gold leaching in thiosulfate-based solutions have been carried out over the years [13] [14] [15][16]. Gold leaching in thiosulphate media is associated with electrochemical ...
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thiourea leaching performance, such as control of redox potential, thiourea concentration, pH, oxidizing agent, and leaching time. However, these conditions are known to vary from
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to the thiourea solution are often carried out to increase the stability of thiourea. However, little attention has been paid to the effect of impurities in the gold ore or thiourea leaching system on thiourea. The gold in RGOs is usually locked by metal …
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Currently, the adsorption methods (e.g., CIP / CIL) are by far dominating the recovery of gold from leaching solutions, especially in cyanide media.
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adshelp[at]cfa.harvard.edu The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement NNX16AC86A
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It was found that used as a buffer, can prevent thiourea from further decomposing into some insoluble species in contact with the oxidant and that the mixed potential of gold is …
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In thiourea-thiocyanate solutions, the gold leaching rate remains constant with time, which means the mixed ligand exhibits behavior similar to thiourea solutions. Increasing ferric concentration leads to a small increase in the gold leaching rate when ferric sulfate concentration increases from 0.0055 M to 0.022 M with no increase
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A mixed-metal solution was used to accurately simulate the spent lixiviant from thiosulfate/thiourea leaching of mine tailings. ... The leaching of gold by thiocyanate solutions is performed at ...
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Since the initial report of thiourea as a complexing reagent for gold leaching, considerable research has been directed toward the use of thiourea as an alternative to cyanide for gold extraction from different auriferous mineral resources. At the same time, some fundamental investigations of the system have been reported. In this article, a review of both …
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Study on the factors influencing thiourea consumption in the gold-leaching process with acidic thiourea solution[J]. Engineering Chemistry and Metallurgy, 1994, 15(3): 229–234. (in Chinese) Google Scholar SA Ben-jia, ZHANG Fang-yu, CHENG Hua. Study on gold dissolving in alkaline thiourea solution [J]. Gold,1984, 5(3):45–47.
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The mechanism of gold dissolution is the theoretical foundations for gold leaching in thiourea solution. The suitable oxidant should be the substances with moderate redox potential. An efficient ...
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The passivation of S 0 on gold leaching in acidic thiourea solution has been found from several previous research (Li & Miller, 2006; Li et al., 2020). The predominance regions of the species of ...
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Several studies demonstrated that Au can be recovered from thiourea leaching solution by adsorption on activated carbon [59,60,61] and organic materials (e.g., persimmon tannin ... Jing-ying L, Xiu-li X, Wen-quan L (2012) Thiourea leaching gold and silver from the printed circuit boards of waste mobile phones. Waste Manag 32(6):1209–1212. ...
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The experiments were conducted at laboratory conditions using ore samples of which approximately 80% were ground to −0.038 mm.The grade of the ore samples was 6.8 g Au/ton.At the first part of the experimental studies, assuming that the gold could be recovered with CIC and CIP processes, the effects of pH, thiourea, oxidizing agent consumption, and leaching …
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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 …
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Oxidants could accelerate the leaching of gold from pretreated sulfide gold ore in thiourea solution. Fe2(SO4)3 is stated as the oxidant promoting the rapid dissolution of gold in thiourea [21]. Researchers have investigated the use of thiourea in the Au leaching process, but they mostly used Fe (III) as an oxidizing agent with a focus only on the
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In addition based on the experimental results, kinetics parameters of first order reaction for gold dissolution were determined for cyanidation and Thiourea leaching separately; therefore for cyanidation, R∞ and K were 95.59% and 0.59 h 1 respectively, while R∞ and K were in order of 78% and 0.87 h 1 for acidic leaching by using Thiourea.
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Under these conditions, gold leaching achieved an ultra-high efficiency, rapidly leaching gold from a roasted gold concentrate within 30 min. Moreover, the addition of NTA into the Fenton/thiourea system lowered the solution potential and eliminated side-reactions between Fe 3+ ions and thiourea, reducing the consumption of thiourea from ...
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The thiourea advantages are a low environmental impact, an easier handling of reagent, a greater selectivity towards gold and silver and fast kinetics of gold dissolution 5, 6.An additional advantage over cyanide exists when treating refractory sulphide gold-containing ore, requiring biooxidative pretreatment; this results in highly acidic solutions, requiring …
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The effects of these stabilizers on the activation energy of alkaline thiourea gold leaching was also studied. The results showed that sodium silicate was more suitable as a stabilizer in this ...
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Kenna, C. and Moritz, P., 1991, "The extraction of gold from bioleached pyrite using novel thiourea leaching technology," In World Gold '91, Gold Forum on Technology & Practice, Second Australia IMM-SME Joint Conference, April 21–26, Melbourne, Australia : Australasian Institute of Mining and Metallurgy, pp. 133 – 137 .
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The thiourea process has been most widely studied mainly because thiourea is not detrimental to the environment, nontoxic to humans, and the dissolution of gold in thiourea solutions is much faster than in cyanide solutions. Dissolution of gold in thiourea solution was reported first in 1941 and continued in 1960s (Lin and Huarng, 1994). It has ...
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Recent research results demonstrate that thiourea decomposition is quite slow in the presence of ferric sulfate for simple solutions. Ferric sulfate and formamidine disulfide …
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