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Leaching of the Mixture of Metallic Gold and Silver

A study on the kinetics of acidic thiourea leaching for gold and silver from a sulfide concentrate containing copper and other valuable metals was carried out. Based on the shrinking core model ...

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Leaching of gold and silver from anode slime …

Leaching experiments of anode slime were performed with several inorganic acids (HCl, HNO_3 and H_2SO_4) together with thiourea and thiosulfate solution to recover gold and silver. Gold was not ...

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Recovery of Gold and Silver from Secondary Sources …

In this study, we investigated two thiourea leach-ing processes for effective recovery of Ag and Au from flue dust. The effects of various parameters on the process, such as leaching time (1–10 h), thiourea concentration (20–60 g/L), pulp density (20–100 g/ L), and leaching temperature (20–60 C), were sys-JOM, Vol. 70, No. 8, 2018

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Thiourea Leaching of Gold and Silver — Technology Update …

Results for the thiourea leaching of a bulk sulfide concentrate and a residue from the autoclave leaching of a smelter flue dust are also reported. As determined by a …

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Thiourea Leaching: An Update on a Sustainable …

was assessed using leaching conditions of 24 g/L thiourea, 0.6% iron (III), pH of 1.00 at 25 °C for a period of two hours. They reported that samples of < 149 µm resulted in around. 90% gold ...

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Microbially enhanced thiourea leaching of gold and silver …

Thiourea was employed as the lixivannt for the extraction of gold and silver in place of the conventional cyanide. Direct thiourea leaching has yielded gold and silver recoveries of 23% and 45% whereas thiourea leaching of the bacterial leach residues has resulted in enhanced gold and silver recoveries of 92% and 78%, respectively.

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Thiourea leaching of gold in presence of jarosite and role …

Thiourea leaching gold and silver from the printed circuit boards of waste mobile phones [J]. Waste Management, 2012, 32: 1209âˆ'1212. [27] ALTANSUKH B, BURMAA G, NYAMDELGER S, ARIUNBOLOR N, SHIBAYAMA A, HAGA K. Gold recovery from its flotation concentrate using acidic thiourea leaching and organosilicon polymer …

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Recovery of Gold and Silver from Secondary Sources of …

Fine materials, such as flue dust, generated during processing of electronic waste (e-waste) contain valuable metal resources, such as Au and Ag. However, …

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Optimization of Gold Dissolution Parameters in …

The nature of gold (Au) ore deposits plays an essential role in determining the best gold recovery method as an alternative to cyanidation, considering environmental concerns. Thiourea (Tu) …

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Leaching of Gold and Silver from Crushed Au-Ag Wastes

The thiourea leaching of gold and silver from electronic waste, goldsmith's waste and ceramic waste using crushing as the pretreatment step was investigated. For electronic waste, it was possible ...

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Selective precipitation separation of gold and silver from thiourea …

A selective and efficient precipitant of gold, silver ions from thiourea leaching solution was proposed. And the effects of factors such as thiourea concentration, metal cation initial ...

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(PDF) Leaching of gold, silver and accompanying metals from circuit

The thiourea leaching of gold and silver from electronic waste, goldsmith's waste and ceramic waste using crushing as the pretreatment step was investigated. For electronic waste, it was possible ...

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Base metal citrate pretreatment of complex ores to improve gold …

Silver leaching with 0.4 M thiourea solutions from the mineral without and with pretreatment (0.5 M citrate solution, pH 8) are compared in Fig. 6. The pretreatment substantially benefited the silver extraction in the thiourea leach, supporting the hypothesis that silver is associated with the galena matrix, and not with iron phases.

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Leaching of silver from solid waste using ultrasound assisted thiourea …

Thiourea leaching of precious metals such as gold and silver from ores has several advantages when compared with conventional cyanidation process. In recent years, the use of ultrasound in leaching processes is becoming increasingly popular in hydrometallurgy. This paper deals with combining these two techniques for silver …

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Leaching of gold from a chalcopyrite concentrate by thiourea

A gold containing chalcopyrite concentrate has been treated with thiourea using H 2 SO 4.The effects of some leach parameters such as thiourea concentration, oxidizing agents, redox potential, pH, temperature, pulp density, acid pretreatment and SO 2 addition have been investigated. Maximum gold and silver extractions are …

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Characterization of Flotation and Leaching in Cyanide and Thiourea …

The experimental results obtained in the flotation and leaching with free cyanide of 2000 mg/L at pH 11.6 and Eh −18 mV and with 0.2 M thiourea at pH 1.5 and Eh + 528 mV of an ore containing gold, silver, and copper show that the flotation is carried out efficiently, however during the leaching in both systems the percentage of dissolution ...

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Leaching of Gold and Silver from Crushed Au-Ag Wastes

The thiourea leaching of gold and silver from electronic waste, goldsmith's waste and ceramic waste using crushing as the pretreatment step was investigated. For electronic waste, it was possible to achieve 97 % gold and 94 % silver recovery within 120 minutes of thiourea leaching. Up to 98 % of gold and 96 % of silver were recovered from gold ...

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Oxidation-free thiourea leaching of gold uthig sulphur …

reagent, high selectivity towards gold, faster leaching kinetics, the possibility of uncovering gold and silver included in acid-soluble minerals, lower dependence of efficiency on the presence of impurity ions. Dissolution of gold in thiourea solutions proceeds in the presence of an oxidizing agent [5, 6] by the following reaction:

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Improved thiourea leaching of gold with additives from …

Acid decomposition and thiourea leaching of silver from hazardous jarosite residues: effect of some cations on the stability of the thiourea system. J. Hazard. Mater. (2016) X.-Y. Chen et al. ... To achieve effective leaching of gold, thiourea was added to facilitate gold extraction. This research not only investigated the leaching conditions ...

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Thiourea leaching gold and silver from the printed circuit boards …

Thiourea is a selective and less hazardous agent as an alternative to the conventional and toxic cyanide. The agent was applied to leach gold and silver from PCBs of waste mobile phones. The influence of the particle size, thiourea and Fe 3+ concentrations and temperature was investigated. In the best condition, about 90% of …

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Thiourea leaching gold and silver from the printed circuit …

The present communication deals with the leaching of gold and silver from the printed circuit boards (PCBs) of waste mobile phones using an effective and less hazardous system, i.e., a thiourea ...

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Improved thiourea leaching of gold from a gold ore using …

The experimental results from thiourea leaching of a gold ore showed that under the optimal conditions of [TU] 0.08 M, [Fe 3+] 0.04 M, pH 2.0, and temperature 40 …

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(PDF) AMENABILITY OF ANTIMONIAL AND ARSENICAL REFRACTORY GOLD/SILVER

The main objective was to determine the mechanism of reaction between thiourea and Fe3+ in the thiourea leaching of gold. Thiourea consumption levels were also examined during the leaching ...

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Stepwise extraction of gold and silver from refractory gold …

Cyanide leaching, as a typical traditional method, hardly achieves the cleaner production of gold due to high consumption of auxiliary materials, inefficient production and heavy environmental pollution.In this work, stepwise thiourea leaching was used to extract gold and silver from refractory gold concentrate calcine. In the first stage, gold and …

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Thiourea leaching of a copper-gold ore using statistical design

Thiourea was used to leach gold from ore containing 0.4% Cu and 5.6 g/t Au. The parameters studied were acid pretreatment, leaching time, pH, thiourea concentration and the oxidizing agents used. ... (18% S), the gold and silver grades are 5.65 g/t and 23 g/t respectively. The major metallic elements are, in order of importance, …

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An innovative thiourea gold leaching process

1.. IntroductionThe use of thiourea, NH 2 CSNH 2, as an extracting agent for precious metals has shown promise for implementation in the metallurgical industry [1].Thioureation has received considerable interest as an alternative lixiviant for gold over the last few years [2].. Laboratory testing has indicated that a thiourea process for gold …

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Improved thiourea leaching of gold from a gold ore using …

Additives such as some reducing or complexing agents have been used to reduce the thiourea consumption. As reported in the literature (Li and Miller, 2006), when SO 2 or Na 2 SO 3 was added into the thiourea solution, thiourea consumption was significantly reduced.However, the SO 2 is a toxic gas and the use of Na 2 SO 3 can …

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Thiourea for Extraction of Gold & Silver from Silver Ores

Leaching Chemistry of Gold Silver and Manganese. 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 SHE), respectively (Kazakov et al., 1983; Lodeishchikov et al., 1975).

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Experimental Study of Thiourea Leaching Gold and Silver …

Waste circuit boards contain a rich resource of recoverable metals such as Cu,Au,Ag,Pt,and Pb.Its disposal,harmless and recycling have become the key problems solved urgently with the economic development.Thiourea leaching gold and silver from the waste circuit board was carried out,and the influence of leaching time,react temperature,thiourea …

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Recovery of Gold and Silver from Secondary Sources of …

In this study, we investigated two thiourea leach-ing processes for effective recovery of Ag and Au from flue dust. The effects of various parameters on the …