Thiourea (TU) is a low-toxicity gold lixiviant that has the promise to replace the highly toxic cyanide for gold extraction. The significant issue of high thiourea consumption and the suspected carcinogenic nature, however, severely restricts its industrial application. In this paper, oxalate and citrate were used as additives to enhance the thiourea leaching of gold from a …
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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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Gold mining is a global business carried out in every continent ex-cept Antarctica. Approximately 190000 tons of gold has been mined since 1950; however, high-quality ores have gradu- ... composition behavior of thiourea during gold leaching with thiourea mixed with pyrite as an impurity was studied to evaluate the effect of pyrite on the ...
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At present, non-cyanide extracting gold methods include thiourea (TU) leaching [6], thiocyanate leaching [7], halogen leaching [8], and thiosulfate (TS) leaching [9], [10].Among them, thiourea [6], halogen [8], and thiocyanate [7] leaching are used to leach gold under acidic conditions, which are corrosive to the equipment, and many base metals ions are dissolved in …
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This review aims to assess the current status of thiourea-gold leaching from e-waste combined with the potential methods for recovering gold from a thiourea gold complex. While previous works have reviewed gold-thiourea leaching from primary ores [52], and others have discussed the status of precious metal recovery from PCB and compared thio-
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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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This review aims to provide an up-to-date evaluation of thiourea-gold leaching studies from electronic waste, with emphasis on the recent progression from the classic …
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Thiourea Silver Leaching. The author concluded that the thiourea technique was uneconomical when compared to traditional cyanidation approaches. A recent paper by Chen, et al. (1980), discusses the leaching of gold and silver by "acidothioureation." Figure 4 compares acidic thiourea and cyanide leaching of gold and silver.
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The cyclic leaching results further suggested that high gold extraction with relatively low thiourea consumption was achieved in five cycles of the citrate-improved thiourea leaching. Thus, citrate-improved thiourea leaching technology appears promising for the extraction of gold from gold ores.
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Although thiourea gold mining has been investigated since 1960, only in the last 20 years has it been seriously considered an alternative to the cyanidation process [33]. Gold leaching by thiourea has been considered due to the rapid reaction with gold [41] and its low price, as well as a lower environmental impact compared to cyanide.
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Besides, these aqueous systems can better meet the fundamental requirements for gold leaching in mining without necessitating changes to the existing cyanidation equipment, ... Reaction chemistry of gold leaching in thiourea solution for a Turkish gold ore. Hydrometallurgy, 67 (2002), pp. 71-77, 10.1016/S0304-386X(02)00136-6.
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However, the interest for thiourea leaching of gold mainly came during the 1980s and 1990s to establish a parallel process. The chemistry of thiourea is simpler than thiosulfate complexation with gold, forming a cationic complex of gold. Various oxidants like oxygen, ozone, sodium peroxide, hydrogen peroxide, ferric ions, dichromate, and ...
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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.
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Gold and Silver Leaching. For Gold and Silver, the most common leachants used are Na or K cyanides in the presence of oxygen, Thiourea (NH 2. CS.NH 2), also in the presence of oxygen, or Ammonium polysulphide (NH 4) 2 Sx, especially for Gold. Optimum physical conditions for cyanidation are: Maximum temperature of 85 o C, Operating ph range of 9 ...
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Thiourea is a reducing and complexing agent and can be used for the processing of gold and silver. The redox potential of gold (I) and silver (I) thiourea complexes in acidic thiourea solutions are 0.380 and 0.023 V (vs …
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alternative gold leaching lixiviants such as thiosulfate, thiourea, and thiocyanate (SCN − ) have been proposed. 1,3−5 It should be mentioned that in the Goldstrike mine, Nevada, of Barrick
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The invention discloses a method for gold leaching by thiourea. When the gold is leached by an acid thiourea solution, aiming at the different gold-containing mine resources, such as the oxidized ore, and the ore pulp or the roasted sand which is obtained after by the hardy-leached sulphide ore is pretreated (oxidized under oxygen pressure, biologically oxidized or roasted) by means …
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When you mix gold ore (usually sulfide gold ore) with acidified thiourea, magic happens. The complex sulfides in the ore get roasted first (kind of like waking them up from a deep slumber). This makes the gold more accessible for leaching. Parameters matter: Leaching time, temperature, pulp density, and thiourea concentration—they all play a ...
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a stibnite concentrate using a thiourea leach, followed by gold recovery onto activated carbon. More recently, Lacoste-Bouchet et al. [40] used thiourea to leach gold from ore
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Thiourea leaching has been reported to be affected to a much lesser degree by the presence of some of these cyanidation inhibitors. In fact, one study suggests that copper, …
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In this research, we studied the use of microwave pretreatment to enhance the efficiency of Au leaching from gold concentrate. The gold concentrate was pretreated using microwaves with different irradiation time. The sample …
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The aim of this experimental work was devoted to the preliminary evaluation of the feasibility of thiourea leaching for the extraction of gold from a domestic gold-bearing ore 4 g/t …
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Thiourea, as an alternative medium, is one of the most promising leaching agents for gold recovery by its commercial benefits and research challenges associated with …
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Discussion This work has adopted a factorial design approach to the assessment of thiourea leaching of the copper-gold ore. Eighteen experiments were used to create a model which describes the leaching of gold on the basis of selected factors. The study showed that acid washing is essential prior to thiourea leaching (Fig. 6).
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Shaking tables are low-capacity machines, ... bioadsorbents are gaining importance in the gold mining circuit. They exhibit high gold selectivity and high gold loading capacity and can be prepared using waste wood, spent papers, citrus wastes, and microalgae residues. ... Microwave pretreatment for thiourea leaching for gold concentrate. Metals ...
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gold leaching process due to the high rate of gold leaching with aci-dothioureation. Since Plaksin et al.1 and Priesler and Scortia2 leached gold by thiourea instead of cyanide in 1941, many reports on the dissolution of gold by thiourea have been published. Groe-newald3 noted that gold could be leached at a much greater rate by
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PDF | On Nov 16, 2022, Johana Borda and others published Prospects for thiourea as a leaching agent in Colombian gold small-scale mining: A comprehensive review | Find, read and cite all the ...
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Prospects for thiourea as a leaching agent in Colombian gold small-scale mining: A comprehensive review . Abstract . Thiourea, as an alternative medium, is one of the most promising leaching agents for gold recovery by its commercial benefits and research challenges associated with performance and environmental impacts.
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TY - JOUR. T1 - THIOUREA LEACHING OF GOLD AND SILVER - TECHNOLOGY UPDATE AND ADDITIONAL APPLICATIONS. AU - Hiskey, J. B. PY - 1984. Y1 - 1984. N2 - The hydrometallurgical application of thiourea in processing precious metal ores and concentrates has reached the development stage.
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Leaching with a relatively concentrated thiourea solution (1MCS (NH2)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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